Time-like concepts: terminology
The term "time" is generally used for many closed but different concepts.
Speaking exactly, one should distinguish at least between:
- instant[1] as an object - one point on the time axes. Being an object, it has no value;
- time interval[2] as an object - part of the time axes limited by two instants. Being an object, it has no value;
- date[3] as a quantity characterizing time instant. Being a quantity, it has value, say, 2014-04-26T09:42:36,75 in the standard form [4], or today, 9:42 a.m. in a colloquial form;
- duration'[5] as a one of quantities characterizing time interval[6]. Being a quantity, it has value, say, 15 minutes. Other quantities describing a time interval are e.g. dates of its begin and end.
From this point of view, the term time can be used as a shorthand or in general sense.
Nevertheless, in an exact text like in definitions, proper term should be chosen:
- effect occurs during time interval of duration Δt = 5 s (full text)
- effect occurs during short time interval (given property of that interval)
- effect occurs during 5 s time interval (given quantity = duration characterizing that interval)
- effect occurs during 5 s (shorthand)
rather than
- effect occurs during time interval Δt = 5 s
because Δt is neither name of that interval nor its value (it is its duration - one of more quantities connected to that interval, other quantity being e.g. date of its start instant).
JOb 12:28, 26 April 2014 (UTC)
Notes and references
- ^ IEC 60050-113:2011, item 113-01-08
- ^ IEC 60050-113:2011, item 113-01-010; ISO 80000-3:2006, item 3-7
- ^ IEC 60050-113:2011, item 113-01-012: "mark attributed to an instant by means of a specified time scale"
- ^ See ISO 8601:2004
- ^ IEC 60050-113:2011, item 113-01-013: "range of a time interval (113-01-10)"
- ^ ISO 80000-3:2006, item 3-7