Tz database
collaborative compilation of information about the world's time zones
The tz database is a collaborative compilation of information about the world's time zones and rules for observing daylight saving time, primarily intended for use with computer programs and operating systems. Paul Eggert has been its editor and maintainer since 2005, with the organizational backing of ICANN. The tz database is also known as tzdata, the zoneinfo database or the IANA time zone database (after the Internet Assigned Numbers Authority), and occasionally as the Olson database, referring to the founding contributor, Arthur David Olson.
Its uniform naming convention for entries in the database, such as America/New_York and Europe/Paris, was designed by Paul Eggert. The database attempts to record historical time zones and all civil changes since 1970, the Unix time epoch. It also records leap seconds.
The database, as well as some reference source code, is in the public domain. New editions of the database and code are published as changes warrant, usually several times per year.
Data structure
Definition of a timezone
Within the tz database, a timezone is any national region where local clocks have all agreed since 1970. This definition concerns itself first with geographic areas which have had consistent local clocks. A timezone is different from a region with a particular standard time offset from UTC, which is often referred to as a "time zone".
The public source identifies “Tz database” as collaborative compilation of information about the world's time zones. This brief keeps that definition visible, then builds a research path around database, collaborative and compilation.
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A short description can identify a subject without explaining its stakes. For “Tz database”, the useful work is to connect “collaborative compilation of information about the world's time zones” to the records capable of establishing context and consequence.
Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Sep 13, 2026. The linked authority identifier is Q187176. None of the 1 selected statements returned an explicit reference. The first chronological checks are 2005 and 1970.
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Questions for further research
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This entry incorporates text from “Tz database” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.