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I know that AM/PM is for ante/post meridiem, but what is it actually called? Meridian indicator? 12 hour indicator? Something way more clever?

JJJ
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Jason
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1 Answers1

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Answer

Oddly enough, this question seems to already have been answered (and then later removed) at StackOverflow. (this is the last existing Wayback Machine backup link to it.)

  • The Unicode standard for date/time formatting calls it "period".

  • Wikipedia says: The 12-hour clock is a time conversion convention in which the 24 hours of the day are divided into two periods

  • Ruby documentation (and probably a lot of strftime references) seems to refer them as "Meridiem Indicator".

From a user interface perspective, a "Period" label is too ambiguous, and "Meridiem Indicator" too pedantic, still leaving "AM/PM" as the best choice.

Aside

As for the actual meanings of AM/PM, they come from the Latin "ante meridiem" ("before noon") and "post meridiem" ("after noon").

Ray Butterworth
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rubergly
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    ha! wtf... why would that be asked on SO? anyways, thanks! – Jason Jul 22 '11 at 22:44
  • any comment on 'ante-meridian'? – Mitch Apr 01 '13 at 04:20
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    @Jason, because software developers think about naming variables properly. It is built into the Object-Oriented mindset. Jader, a commenter, said it well: "It's funny that the question intrinsically is not programming related, but all programmers can understand why you posted it here." – rajah9 Jun 03 '13 at 16:51
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    @rajah9 this is actually why i asked this question in the first place ;) – Jason Jan 07 '14 at 18:34
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    @Json and that was the reason I found your post XD – BananaAcid Dec 28 '18 at 02:31
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    The deleted SO post suggests "Meridiem Indicator" as an alternate term that is less ambiguous than "period" – divibisan Apr 02 '19 at 15:25
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    @rajah9 That's why I'm here :). I wanted to properly name my variable. – Bob Oct 29 '19 at 14:29
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    Also here to properly name a variable. :) – Rob Johansen May 16 '20 at 00:59
  • interesting answer, but you don't cite any sources for why that is an accepted or generally valid term to use for it – simpleuser Jun 19 '20 at 17:17

  • leaving "AM/PM" as the best choice

    Not exactly so, IMO. In German it's nachts ("at night") & morgens ("in the morning"). And, in Japanese, it can be written 午後 (gogo, afternoon; P.M.) & 午前 (gozen, morning; A.M.) (before the time values). I think I will use meridiem or meridiemIndicator.

     – ryanttb Apr 05 '23 at 16:47