ISO 4

{{short description|International standard which defines a uniform system for the abbreviation of serial titles}}

{{Use British English Oxford spelling|date=December 2011}}

ISO 4 (Information and documentation — Rules for the abbreviation of title words and titles of publications) is an international standard which defines a uniform system for the abbreviation of serial publication titles, i.e., titles of publications such as scientific journals that are published in regular installments.{{cite web|url=http://www.issn.org/services/online-services/access-to-the-ltwa/|title=Online services: Access to the LTWA|publisher=International Standard Serial Number International Centre|access-date=22 October 2014|archive-date=7 July 2018|archive-url=https://web.archive.org/web/20180707185635/http://www.issn.org/services/online-services/access-to-the-ltwa/|url-status=live}}

The International Organization for Standardization (ISO) has appointed the ISSN International Centre as the registration authority for ISO 4. It maintains the List of Title Word Abbreviations (LTWA), which contains standard abbreviations for words commonly found in serial titles. {{as of|2017|August}}, the standard's most recent update came in 1997,{{Cite book|title=Elements of Information Organization and Dissemination.|last=Amitabha|first=Chatterjee|publisher=Chandos|year=2016|isbn=978-0-08-102026-5|pages=493|oclc=962412353}} when its third edition was released.{{Cite web |url=https://www.iso.org/standard/3569.html |url-access=subscription |title=ISO 4:1997 Information and documentation — Rules for the abbreviation of title words and titles of publications |publisher=International Organization for Standardization |access-date=2019-03-24 |archive-date=24 March 2019 |archive-url=https://web.archive.org/web/20190324141230/https://www.iso.org/standard/3569.html |url-status=live }}

A major use of ISO 4 is to abbreviate the names of scientific journals using the LTWA. For instance, under ISO 4 standards, the Journal of Biological Chemistry is cited as J. Biol. Chem., and the Journal of Polymer Science Part A should be cited as J. Polym. Sci. A (capitalization is not specified by the standard). The standard notes that "Full stops shall only be used to indicate an abbreviation. Full stops may be omitted from abbreviated words in applications that require limited use of punctuation" (section 4.6).

It was initially published in 1972 (ISO 4:1972),{{Cite web | url=https://www.iso.org/standard/3567.html | title=ISO 4:1972 Documentation — International code for the abbreviation of titles of periodicals | publisher=International Organization for Standardization | access-date=2019-03-24 | archive-date=8 July 2023 | archive-url=https://web.archive.org/web/20230708025239/https://www.iso.org/standard/3567.html | url-status=live }} with a second edition published in 1984 (ISO 4:1984),{{Cite web |url=https://www.iso.org/standard/3568.html |title=ISO 4:1984 Documentation — Rules for the abbreviation of title words and titles of publications |publisher=International Organization for Standardization |access-date=2019-03-24 |archive-date=21 April 2023 |archive-url=https://web.archive.org/web/20230421082509/https://www.iso.org/standard/3568.html |url-status=live }} and the third edition in 1997 (ISO 4:1997).