# “Position” is to “space” as what word is to “time”?

Is there an English word that is the temporal equivalent to "position"? As position can be described as "where you are", I can think of "when you are" as the temporal meaning.

Information on how it will be used in order to be answered (quoted from a comment by the OP which has since been moved to chat):

If a time traffic controller were to speak to a time traveller, though, can he say "I'll need you to supply your current moment please before we can arrange your landing."? Or does it only feel unnatural because we never use moment like that. Because we don't have time travel to require lingo like that?

• Comments are not for extended discussion; this conversation has been moved to chat. – tchrist Mar 31 '18 at 0:22

A moment (in time), according to Collins Dictionary a moment is:

"a specific instant or point in time"

Attribution: "Definition of 'moment'." Moment Definition and Meaning | Collins English Dictionary. Accessed March 27, 2018. https://www.collinsdictionary.com/dictionary/english/moment.

• Comments are not for extended discussion; this conversation has been moved to chat. – tchrist Mar 31 '18 at 0:23

Technically and even mathematically speaking, that would be an instant, which can be thought of as a more technical term for a moment. This is how Wikipedia defines it:

An instant is an infinitesimal moment in time, a moment whose passage is instantaneous.

For example:

The object was in this position (these coordinates) at this instant in time.

Mathematically, the precise position of an object can be described using a position function. Thus, we are always able to say precisely what position the object is in at any particular instant (moment) in time. You plug in a particular instant of time (t) into the position function, and out pops its position precisely at that instant (or moment). That's literally the kind of lingo that mathematicians would use.

• Agreed, not least because the technical definition of 'moment' refers to torque physics and movement. Using it for time, whilst natural, would be confusing. – mcalex Mar 28 '18 at 7:39
• @mcalex I’m pretty sure it’s called ‘momentum’ in that case. – Alexander Revo Mar 28 '18 at 12:03
• @AlexanderRevo There is a physics concept of "moment" that is not the same as "momentum". Most commonly that I've seen, "Moment of inertia". – Kamil Drakari Mar 28 '18 at 14:59
• +1. An instant and a position has zero duration in time and zero expanse in space, respectively. – Christoffer Lette Mar 28 '18 at 19:43
• @Ooker Following AlexanderRevo's comment, I figured 'momentum' was a derivative of moment. This is incorrect, but it appears moment is actually derived from momentum. A Momentum was a medieval unit of time, measured by the movement of the indicator on a sundial (and is about 90 seconds). This movement around a circle is conceptually similar to torque which is a rotating force. Links to simple and complex explanations – mcalex Mar 29 '18 at 6:44

"Time"!

At least, that's the word we most often use for what you might call the "temporal coordinate" of an event, analogous to the position of an event being its "spatial coordinate". For example, one might say that the position of an event was the north-west corner of the building and the time of the event was 7:34pm.

Other answers have suggested things like "moment" or "instant". These are good if you want a word meaning "a location in time" analogous to position being "a location in space".

• "Moment" and "instant" both have connotations of a very short, specific time. Like one might say, "The instant that Caesar crossed the Rubicon, the Roman Republic was doomed", but you wouldn't say, "The instant of the Roman Republic was from 509 BC to 27 BC". You might say, "The time of the Roman Republic was from 509 BC to 27 BC". – Jay Mar 29 '18 at 17:11
• @Jay I agree—to my mind, that makes this answer even more appropriate. A "location" is not a singularity; it could be one square nanometer, or several city blocks, or a continent, depending on the thing being located; similarly, "time" can be a single instant or a geological eon, e-tc. "Where are you, and what time is it?" "I'm at GPS coordinate X, at 2018-03-29 20:53:42z" OR "I'm in the Milky Way Galaxy, estimated 14 billion years post-Big Bang." – 1006a Mar 29 '18 at 20:53
• For less specific times, we use words like "day", "month", "year", etc. – Barmar Mar 30 '18 at 2:39
• You've correctly stated that "time" is the correct word in the third spot in the analogy, but didn't supply the missing word (which is actually the fourth spot). I suggest that eternity and history both can play that role, completing the analogy: Position is to space as time is to eternity. – Ben Voigt Mar 31 '18 at 19:02
• @BenVoigt The question asks "'Position' is to 'space' as what word is to 'time'?" That is, it wants us to fill in the blank in "'Position' is to 'space' as ______ is to 'time'." "Eternity" would be an answer if the question was "'Position' is to 'space' as 'time' is to what?" but (a) that's not the question; (b) "time" would be a valid answer to that question, too. – David Richerby Mar 31 '18 at 20:54

I'd suggest "Point in time"

"Point in time is sometimes useful, though. It may indicate that point refers to time instead of space—though context usually fills in the blank. And when it comes to point in time (and similarly with point in space), one can bypass this issue by removing point in and keeping time."

http://grammarist.com/usage/point-in-time/

Position is a word that locates a particular spot in space. A date locates a particular 'spot' in time at the granularity of '1 Day'. For granularity finer than a day, people often ask for the date and time, where time is understood to be the time of day (e.g. 3pm), and can be expressed to whatever precision is required.

date noun 1.1 A particular day or year when a given event occurred or will occur. ‘they've set a date for the wedding’ - ODO

• In a scientific context, "date" is also used to refer to a fixed point in time -- regardless of its unit (it can be precise to the hour/minute/second/etc). – Florian Castellane Mar 28 '18 at 11:20

For terms like this, I’d try to get standard language from the software world as that will normally be very carefully thought out and peer reviewed,

A well known new software library uses date-time.

A date-time without a time-zone in the ISO-8601 calendar system, such as 2007-12-03T10:15:30. https://docs.oracle.com/javase/9/docs/api/java/time/LocalDateTime.html

Epoch.

'Interval' refers to a range of time, either between two fixed points or one fixed point and an unknown end (such as 'from now to the end of time'), OR of specified length. 'Epoch' refers to a position along the universal timeline.

Note that in the vernacular, 'epoch' is often used to refer to an historical era. In more scientific notation, 'epoch' refers to the time coordinate in a space-time event (x='horizontal', y='vertical', z='depth', t='epoch').

• In computing, Epoch means the DateTime that the current DateTime is measured relative to. Traditionally, this is in seconds since 1 Jan 1970 00:00:00 UTC; it is now 1522253658 seconds since then – CSM Mar 28 '18 at 16:14
• To expound on @CSM 's comment, in computing, "epoch" is analogous to the "origin" in cartesian coordinates; just as the origin is the point that is assigned x and y coordinates of zero, the epoch is the moment that is assigned t coordinate of zero. – Acccumulation Mar 29 '18 at 16:08

While moment and instant are the best answers for a particular point in time, other similar words for longer "time locations" are:

• duration, also extent, period, run, stretch - These can be specified with precision, like position.
• while, also span, tide, spell - These are more conversational, like place.

There is no specific word in common English. (Fiction writers may have invented words not in wide use). In particular, proposed answers "moment" and "instant" do not answer the question.

This can be seen by imagining asking an aircraft, lifeboat, or someone who is lost in fog on a mountain, but has GPS, or even someone in an imaginary landscape such as VR or a hallucination, "what is your position?" This would be completely common understood English.

But you would not ask someone confused about when it is, or somehow "lost in time", or in a VR or hallucination, whose personal impression was sought, "What is your moment?" in ordinary English, and there is no phrase that does ask this in one word, that I know of. You just wouldn't.

What you might ask is, "When is it, where you are" or similar.

Speculatively, the reason we have one word but not the other, is because we don't tend to get lost in time, or have to report our current chronolocation, whereas we frequently have to report our spatial location.

When someones location in time is sought, as far as we know (and relativity and microseconds difference aside), the answer for all humans on Earth has always been "now", or "the same as for you", so in practice, the question which is common for space, never usually arises about time, nor was there a need for a word like this to emerge.

In IT, the term timestamp is often used, for example, the CURRENT_TIMESTAMP function in SQL standard.

• A "timestamp" is a sequence of characters that represent a description of an instant or moment in time as recorded against some event. That is not the same as the actual instant or moment itself. – Lightness Races in Orbit Mar 28 '18 at 12:54
• @LightnessRacesinOrbit, that's technically true, but in the context of (say) analyzing user behavior from server logs, the terms are essentially interchangeable. – smci Mar 29 '18 at 21:45
• @smci: But not, in my opinion, in the context of this question. – Lightness Races in Orbit Mar 29 '18 at 23:13
• I agree with @LightnessRacesinOrbit; timestamp is not the analog of the concept of position, it's analogous to numerical coordinates with some finite limits on precision, way of recording a time as data. – Adam Smith Mar 31 '18 at 5:16

## protected by tchrist♦Mar 31 '18 at 0:24

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