ISO 34000:2023

Overview

ISO 34000:2023 - Date and time - Vocabulary is the first edition (2023) ISO vocabulary for date and time concepts. It defines standardized terms and explanations ranging from fundamental notions (date, time, instant, duration) to specialized concepts (time scales, proper and coordinate time, calendar systems, time units and representations). The document supports consistent use of date/time terminology across technical, scientific and administrative domains and references related bodies such as ITU‑R and the BIPM SI Brochure where appropriate.

Key topics

The standard organizes terminology into clear topic areas and definitions, including:

• General concepts: date, time, instant, time axis, time interval, duration, time of day.
• Time scales: definitions and examples of continuous scales (TAI), discontinuous scales (UTC with leap seconds), discrete scales and calendar-based scales.
• Proper and coordinate time: distinctions between clock‑measured proper time and coordinate time used in space‑time coordinates.
• Basis and standard time: basis time scales (GNSS system times) and derived standard/local times (UTC offsets, daylight saving/time shifts).
• Time scale units and representations: SI second, minute, hour, day, calendar units and how durations can vary (e.g., leap seconds, varying month lengths).
• Expressions and representations: vocabulary covering common date formats (calendar date, ordinal date, week date) and rules for recurring intervals.

Practical applications and users

ISO 34000:2023 is valuable wherever precise, interoperable date/time language is required:

• Software and database developers implementing timestamps, logging and time APIs.
• Telecommunications and GNSS (GPS, Galileo, GLONASS) engineers dealing with system times and offsets.
• Legal, financial and regulatory bodies that require unambiguous recordkeeping and time‑stamping.
• Scientific and metrology communities handling coordinate time, proper time and SI‑based durations.
• Standards writers, technical writers and system integrators who need consistent terminology for documentation and data exchange.

Benefits include improved interoperability, reduced ambiguity in specifications and clearer communication about time‑related behaviors such as leap seconds and daylight saving transitions.

Related standards

• IEC 60050‑113 (vocabulary elements used in some definitions)
• ISO 8601‑2:2019 (rules for recurring time intervals referenced)
• ITU‑R TF.2018 and the BIPM SI Brochure (background on proper/coordinate time and SI second realizations)

Keywords: ISO 34000:2023, date and time vocabulary, time scale definitions, UTC, TAI, calendar systems, leap seconds, time units, timestamp interoperability.