Interpretation Act, 1923

What is this act about?

This law, the Interpretation Act, 1923, sets out rules for understanding and interpreting other laws passed by the Oireachtas, and defines common words and phrases used in those laws. Its purpose is to clarify the meaning, construction, and operation of Acts of the Oireachtas and related legal instruments.

Who it applies to: Anyone who needs to understand or apply Acts passed by the Oireachtas; Courts and legal professionals interpreting legislation.

At a glance

Country: Ireland
Area of law: Real estate and construction law
Articles: 19
Source: irishstatutebook.ie
Text retrieved: 2026-06-17
Explanation updated: 2026-07-07

What does this act regulate?

The meaning of general words like "person," "month," and "land" in Acts.
The definition of specific official and geographical terms used in Acts.
The interpretation of judicial expressions and certain general expressions within Acts.
General rules for how Acts should be understood and applied.

Who does this act apply to?

Anyone who needs to understand or apply Acts passed by the Oireachtas.
Courts and legal professionals interpreting legislation.

What are the key points?

Words importing the masculine gender include females.
Words in the singular include the plural, and vice versa.
The word "person" includes any body of persons, corporate or un-incorporate.
"Month" means calendar month.

Real estate and construction law

Transport (Dublin Light Rail) Act, 1996

Housing (Amendment) Act, 1944

Housing Act, 1929

Local Government (Roads and Drainage) Act, 1968

Cork Fever Hospital Act, 1935

Planning and Development and Foreshore (Amendment) Act 2022

Cork Fever Hospital (Amendment) Act, 1954

Dublin Reconstruction (Emergency Provisions) Act, 1924

Real estate and construction law

Legal text

Contents (19)

Section 1
Section 2
Section 3
Section 4
Section 5
Section 6
Section 7
Section 8
Section 9
Section 10
Section 11
Section 12
Section 13
Section 14
Section 15
Section 16
Section 17
Section 18
Section 19

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INTERPRETATION ACT, 1923.

ARRANGEMENT OF SECTIONS Section

Section 1

Construction of certain general words in Acts.

Section 2

Meaning of certain official expressions in Acts.

Section 3

Meaning of certain geographical expressions in Acts.

Section 4

Meaning of certain judicial expressions in Acts.

Section 5

Meaning of certain general expressions in Acts.

Section 6

Meaning of the expression “rules of court”.

Section 7

Certain general rules for the construction of Acts.

Section 8

Date of passing and coming into operation of Acts.

Section 9

Marginal and other notes not part of Act.

Section 10

Acts to be judicially noticed, and sections to be substantive enactments.

Section 11

Rules of construction relating to the commencement of Acts.

Section 12

Construction of provisions as to exercise of powers and duties.

Section 13

Construction and effect of repeals of Acts.

Section 14

Construction of statutory rules, etc.

Section 15

Provisions as to offences under two or more laws.

Section 16

Acts may be repealed, etc., in the same session.

Section 17

Citation of Acts.

Section 18

Application of the Interpretation Act 1889.

Section 19

Short Title.

Acts Referred to Irish Free State (Saorstát Eireann) Act, 1922 No. 1 of 1922 Comptroller and Auditor-General Act, 1923 No. 1 of 1923 Adaptation of Enactments Act, 1922 No. 2 of 1922 Number 46.

INTERPRETATION ACT, 1923.

AN ACT TO PRESCRIBE RULES FOR THE CONSTRUCTION OF ACTS OF THE OIREACHTAS, AND TO DEFINE THE MEANING OF CERTAIN WORDS AND EXPRESSIONS COMMONLY USED IN SUCH ACTS, AND FOR OTHER PURPOSES RELATING TO THE MEANING, CONSTRUCTION, AND OPERATION OF ACTS OF THE OIREACHTAS AND OF INSTRUMENTS MADE UNDER THE AUTHORITY THEREOF. [28th December, 1923.] BE IT ENACTED BY THE OIREACHTAS OF SAORSTÁT EIREANN AS FOLLOWS:— Construction of certain general words in Acts.

1.—(1) In this Act and in every Act passed after the commencement of this Act, unless the contrary intention appears— (a) words importing the masculine gender shall include females: (b) words in the singular shall include the plural, and words in the plural shall include the singular: (c) the word ‘person’ shall include any body of persons corporate or un-incorporate: (d) the word ‘month’ shall mean calendar month: (e) the word ‘land’ shall include messuages, tenements, and hereditaments, houses and buildings, of any tenure: (f) the words ‘oath’ and ‘affidavit’ shall, in the case of persons for the time being allowed by law to affirm or declare instead of swearing, include affirmation and declaration, and the word ‘swear’ shall, in the like case, include affirm and declare.

(2)In the construction of every enactment relating to an offence punishable on indictment or on summary conviction, the word ‘person’ shall, unless the contrary intention appears, include a body corporate.

Meaning of certain official expressions in Acts.

2.—In this Act and in every Act passed after the commencement of this Act, the following expressions shall, unless the contrary intention appears, have the meanings hereby respectively assigned to them, namely:—

(1)the expressions “the Constitution” and “the Constitution of Saorstát Eireann” shall mean the Constitution set forth in the First Schedule annexed to the Constitution of the Irish Free State (Saorstát Eireann) Act, 1922 (No. 1 of 1922):

(2)the expression “the Governor-General” shall mean the Governor-General of the Irish Free State (Saorstát Eireann) for the time being:

(3)the expression “the Comptroller and Auditor-General” shall mean the Comptroller of the Receipt and Issue of the Exchequer of Saorstát Eireann and Auditor-General of Public Accounts for the time being appointed under the Comptroller and Auditor-General Act, 1923 (No. 1 of 1923):

(4)the expression “the Executive Council” shall mean the Executive Council for the time being constituted and appointed in accordance with the provisions of the Constitution:

(5)the expressions “the President” and “the Vice-President” shall respectively mean the President and the Vice-President for the time being of the Executive Council:

(6)the expression “an Executive Minister” shall mean a Minister who is for the time being a member of the Executive Council:

(7)The expression “the First Dáil Eireann” shall mean the assembly of members of Parliament elected for constituencies in Ireland at a Parliamentary Election held on the 14th day of December, 1918, who first came together in a Parliament held on the 21st day of January, 1919, in the official residence of the Lord Mayor of Dublin called the Mansion House at Dublin, and there drew up and promulgated a provisional constitution for the said assembly as Dáil Eireann and Government of Saorstát Eireann:

(8)the expression “the Second Dáil Eireann” shall mean the assembly of members of Parliament elected for constituencies in Ireland at a Parliamentary Election held on the 13th day of May, 1921, who met as Dáil Eireann and Government of Saorstát Eireann in a Parliament held at Dublin in the Mansion House aforesaid on the 16th day of August, 1921:

(9)the expression “the Third Dáil Eireann” shall mean the assembly of members of Parliament elected by an Election held pursuant to a Resolution of the Second Dáil Eireann passed on the 20th day of May, 1922, and in manner particularly mentioned in an Act of the United Kingdom Parliament entitled “The Irish Free State (Agreement) Act, 1922,” in which Act the said Dáil Eireann is referred to as the House of the Parliament to which the Provisional Government shall be responsible being the constituent assembly which enacted the Constitution:

(10)the expression “the Treaty of 1921” shall mean the Articles of Agreement for a Treaty between Great Britain and Ireland signed at London on the 6th day of December, 1921, and subsequently approved and ratified by the Second Dáil Eireann and by the United Kingdom Parliament respectively, the text whereof is set forth in the Second Schedule to the Constitution of the Irish Free State (Saorstát Eireann) Act, 1922 (No. 1 of 1922):

(11)the expression “the United Kingdom Parliament” shall mean the Parliament of the late United Kingdom of Great Britain and Ireland:

(12)the expression “British Statute” shall mean an Act of the United Kingdom Parliament continued in force and effect in Saorstát Eireann by Article 73 of the Constitution:

(13)the expression “the Bank of Ireland” shall mean, as circumstances require, the Governor and Company of the Bank of Ireland or the bank of the Governor and Company of the Bank of Ireland.

Meaning of certain geographical expressions in Acts.

3.—In this Act and in every Act passed after the commencement of this Act, the following expressions shall, unless the contrary intention appears, have the meanings hereby respectively assigned to them, namely:—

(1)the expression “Saorstát Eireann” or its equivalent in English “the Irish Free State” when used for the purpose of defining the application of any law or the extent or incidence of any authority, obligation or imposition shall mean the area for the time being within the jurisdiction of the Parliament and Government of Saorstát Eireann:

(2)the expression “Northern Ireland” shall mean such part of Ireland as the powers of the Parliament and Government of Saorstát Eireann shall for the time being not extend to:

(3)the expression “Great Britain” shall mean England, Wales and Scotland:

(4)the expressions “England,” “Wales,” “Scotland,” “Ireland” and “Saorstát Eireann” shall respectively include the islands (other than the Channel Islands and the Isle of Man) adjacent to the coasts thereof.

Meaning of certain judicial expressions in Acts.

4.—In this Act and in every Act passed after the commencement of this Act, the following expressions shall, unless the contrary intention appears, have the meanings hereby respectively assigned to them, namely:—

(1)the expression “Supreme Court” shall mean the Supreme Court of Justice in Saorstát Eireann:

(2)the expression “High Court” shall mean the High Court of Justice in Saorstát Eireann:

(3)the expression “Circuit Court” shall mean the Circuit Court of Justice in Saorstát Eireann:

(4)the expression “District Court” shall mean the District Court of Justice in Saorstát Eireann:

(5)the expression “court of summary jurisdiction” shall mean a District Court:

(6)the expression “the Summary Jurisdiction Acts” shall mean, as respects the Dublin Metropolitan Police District, the several Acts for the time being regulating the powers and duties of District Justices and the police in that District, and as respects any other part of Saorstát Eireann, the Petty Sessions (Ireland) Act, 1851 , and all Acts past and future for the time being in force amending that Act:

(7)the expression “Lands Clauses Acts” shall mean the Lands Clauses Consolidation Act, 1845 , the Lands Clauses Consolidation Acts Amendment Act, 1860 , the Railways Act (Ireland), 1851 , the Railways Act (Ireland), 1860 , the Railways Act (Ireland), 1864 , and the Railways Traverse Act, and every Act for the time being in force amending those Acts or any of them:

(8)the expression “Valuation Acts” shall mean the Acts for the time being in force relating to the valuation of rateable property in Saorstát Eireann.

Meaning of certain general expressions in Acts.

5.—In this Act and in every Act passed after the commencement of this Act, the following expressions shall unless the contrary intention appears, have the meanings hereby respectively assigned to them, namely:—

(1)the expression “financial year” shall mean as respects any matters relating to the Central Fund, or to money provided by the Oireachtas, or to the Exchequer, or to any taxes imposed by the Oireachtas of Saorstát Eireann, or otherwise to the finance of Saorstát Eireann, the twelve months ending on the 31st day of March:

(2)the expression “statutory declaration” shall mean a declaration made by virtue of the Statutory Declarations Act, 1835:

(3)the expression “ordnance map” shall mean a map made under the powers conferred by the Survey (Ireland) Acts, 1825 to 1870, and every Act for the time being in force amending those Acts or any of them.

Meaning of the expression “rules of court.”

6.—(1) In this Act and in every Act passed after the commencement of this Act, unless the contrary intention appears, the expression “rules of court” when used in relation to any court, shall mean rules made by the authority having for the time being power to make rules or orders regulating the practice and procedure of such court.

(2)The power of every authority having for the time being power to make rules or orders regulating the practice and procedure of any court shall (whether such authority was established before or after the passing of this Act) include a power to make rules of court for the purpose of any Act passed after the commencement of this Act and directing or authorising anything to be done in relation to that court by rules of court.

Certain general rules for the construction of Acts.

7.—(1) In this Act and in every Act passed after the commencement of this Act all expressions relating to time, and every reference to a point of time shall, unless the contrary intention appears, be construed as relating or referring to Greenwich mean time, but subject to the provisions of any enactment for the time being in force providing for the time in Saorstát Eireann being in advance of Greenwich mean time during any specified period.

(2)In the measurement of any distance for the purposes of any Act passed after the commencement of this Act, that distance shall, unless the contrary intention appears, be measured in a straight line on a horizontal plane.

(3)In this Act and in every Act passed after the commencement of this Act, expressions referring to writing shall, unless the contrary intention appears, be construed as including references to printing, typewriting, lithography, photography, and other modes of representing or reproducing words in a visible form.

(4)Where an Act passed after the commencement of this Act authorises or requires any document to be served by post, whether the expression “serve,” or the expression “give,” “deliver” or “send,” or any other expression is used, then, unless the contrary intention appears, the service shall be deemed to be effected by properly addressing, prepaying, and posting a letter containing the document, and, unless the contrary is proved, such service shall be deemed to have been effected at the time at which the letter would be delivered in the ordinary course of post.

(5)In any Act passed after the commencement of this Act a description of or citation from any other Act, instrument or document shall, unless the contrary intention appears, be construed as including the word, section, or other part mentioned or referred to as forming the beginning or as forming the end of the portion comprised in the description or citation.

Date of passing and coming into operation of Acts.

8.—(1) The date of the passing of this Act and every other Act of the Oireachtas whether passed before or after this Act shall be the day on which the Representative of the Crown signifies, pursuant to Article 41 of the Constitution, the King's assent to the Bill for such Act.

(2)Immediately after the passing of this Act and immediately after the passing of every Act passed after this Act, the Clerk of the Dáil shall endorse on such Act immediately after the title thereof the date on which such Act was passed, and such endorsement shall be taken to be part of the Act.

(3)Every Act passed after this Act shall come into operation immediately on the passing thereof unless the contrary intention is expressed.

Marginal and other notes not part of Act.

9.—No marginal note, heading, or other note placed at the side, head, or foot of any section or group of sections of this Act or of any other Act of the Oireachtas, whether passed before or after this Act, to indicate the subject, contents, or effect of the section or group of sections shall be taken to be part of the Act or be considered or judicially noticed in relation to the construction or interpretation of the Act.

Acts to be judicially noticed, and sections to be substantive enactments.

10.—(1) This Act and every Act passed after the commencement of this Act, shall be a public Act and shall be judicially noticed unless the contrary is expressly provided by the Act.

(2)Every Act passed after the commencement of this Act shall be divided into sections numbered consecutively.

(3)Every section of this Act and of every Act passed after the commencement of this Act shall have effect as a substantive enactment without introductory words.

Rules of construction relating to the commencement of Acts.

11.—(1) In this Act, and in every Act passed after the commencement of this Act, the word “commencement,” when used with reference to an Act, shall mean the time at which the Act comes into operation.

(2)Where an Act passed after the commencement of this Act, or any order, warrant, scheme, letters patent, rules, regulations, or byelaws made, granted, or issued under a power conferred by any such Act, is expressed to come into operation on a particular day, the same shall be construed as coming into operation immediately on the expiration of the previous day.

(3)Where an Act passed after the commencement of this Act is not to come into operation immediately on the passing thereof, and confers power to make any appointment, to make, grant, or issue any instrument, that is to say, any order, warrant, scheme, letters patent, rules, regulations, or byelaws, to give notices, to prescribe forms, or to do any other thing for the purposes of the Act, that power may, unless the contrary intention appears, be exercised at any time after the passing of the Act, so far as may be necessary or expedient for the purpose of bringing the Act into operation at the date of the commencement thereof, subject to this restriction, that any instrument made under the power shall not, unless the contrary intention appears in the Act, or the contrary is necessary for bringing the Act into operation, come into operation until the Act comes into operation.

Construction of provisions as to exercise of powers and duties.

12.—(1) Where an Act passed after the commencement of this Act confers a power or imposes a duty, then, unless the contrary intention appears, the power may be exercised and the duty shall be performed from time to time as occasion requires.

(2)Where an Act passed after the commencement of this Act confers a power or imposes a duty on the holder of an office as such, then, unless the contrary intention appears, the power may be exercised and the duty shall be performed by the holder for the time being of the office.

(3)Where an Act passed after the commencement of this Act confers a power to make any rules, regulations, or byelaws, the power shall, unless the contrary intention appears, be construed as including a power, exerciseable in the like manner and subject to the like consent and conditions, if any, to rescind, revoke, amend, or vary the rules, regulations, or byelaws.

Construction and effect of repeals of Acts.

13.—(1) Where this Act or any Act passed after the commencement of this Act repeals and re-enacts with or without modification, any provisions of a former Act, references in any other Act to the provisions so repealed, shall, unless the contrary intention appears, be construed as references to the provisions so re-enacted.

(2)Where this Act or any Act passed after the commencement of this Act repeals any other enactment, then, unless the contrary intention appears, the repeal shall not— (a) revive anything not in force or existing at the time at which the repeal takes effect; or (b) affect the previous operation of any enactment so repealed or anything duly done or suffered under any enactment so repealed; or (c) affect any right, privilege, obligation, or liability acquired, accrued, or incurred under any enactment so repealed; or (d) affect any penalty, forfeiture, or punishment incurred in respect of any offence committed against any enactment so repealed; or (e) affect any investigation, legal proceeding, or remedy in respect of any such right, privilege, obligation, liability, penalty, forfeiture, or punishment as aforesaid; and any such investigation, legal proceeding, or remedy may be instituted, continued, or enforced, and any such penalty, forfeiture, or punishment may be imposed, as if the repealing Act had not been passed.

(3)Where an Act passed after the commencement of this Act, repeals wholly or partially any former enactment and substitutes provisions for the enactment repealed, the repealed enactment shall remain in force until the substituted provisions come into operation.

Construction of statutory rules, etc.

14.—Where any Act, passed after the commencement of this Act, confers power to make, grant, or issue any instrument, that is to say, any order, warrant, scheme, letters patent, rules, regulations, or byelaws, words and expressions used in the instrument shall, unless the contrary intention appears, have the same respective meanings as in the Act conferring the power.

Provisions as to offences under two or more laws.

15.—Where an act or omission constitutes an offence under two or more Acts, or both under an Act and at common law, whether any such Act was passed before or after the commencement of this Act, the offender shall, unless the contrary intention appears, be liable to be prosecuted and punished under either or any of those Acts or at common law, but shall not be liable to be punished twice for the same offence.

Acts may be repealed, etc., in the same session.

16.—An Act passed in any session of the Oireachtas may be altered, amended, or repealed by any Act passed later in the same session.

Citation of Acts.

17.—(1) This Act and every other Act of the Oireachtas, whether passed before or after this Act, may be cited in any Act, instrument, or document by reference to the short title of the Act or by reference to the calendar year in which the Act was passed and the consecutive number of the Act in that year.

(2)Any enactment of the Oireachtas contained in this Act or in any other Act of the Oireachtas, whether passed before or after this Act, may be cited by reference to the section or sub-section of the Act in which the enactment is contained.

Application of the Interpretation Act 1889.

18.—(1) The Interpretation Act, 1889, as modified and adapted by or under the Adaptation of Enactments Act, 1922 (No. 2 of 1922) shall apply and be deemed always to have applied to every Act of the Oireachtas passed before the commencement of this Act (except this Act), and to every order, rule, regulation, or other instrument made, whether before or after the commencement of this Act, under the authority of an Act of the Oireachtas passed before the commencement of this Act or partly under the authority of such Act and partly under the authority of an Act of the United Kingdom Parliament.

(2)The Interpretation Act, 1889, shall not apply to this Act or to any Act passed after the commencement of this Act or to any order, rule, regulation, or other instrument made under the authority of any such Act or partly under the authority of any such Act and partly under the authority of an Act passed by the Oireachtas before the commencement of this Act or of an Act of the United Kingdom Parliament.

Short Title.

19.—This Act may be cited as the Interpretation Act, 1923, and shall come into operation on the 1st day of January, 1924.

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