12-hour clock: Difference between revisions
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The '''12 hour clock''' is a time-keeping convention in which the 24 hours of the [[day]] are divided into two periods of 12 [[hour]]s, "am" and "pm". |
The '''12 hour clock''' is a [[time-keeping]] convention in which the 24 hours of the [[day]] are divided into two periods of 12 [[hour]]s, "am" and "pm". |
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'''AM''' is short for ''ante meridiem'', [[Latin language|Latin]] for "before noon". This is used to define hours of the day: "The meeting starts at 9 am." The opposite of am is '''PM''', which is short for ''post meridiem'', [[Latin language|Latin]] for "after noon". This is used to define hours of the day: "The meeting ends at 5 pm." |
'''AM''' is short for ''ante meridiem'', [[Latin language|Latin]] for "before noon". This is used to define hours of the day: "The meeting starts at 9 am." The opposite of am is '''PM''', which is short for ''post meridiem'', [[Latin language|Latin]] for "after noon". This is used to define hours of the day: "The meeting ends at 5 pm." |
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Revision as of 17:14, 6 June 2003
The 12 hour clock is a time-keeping convention in which the 24 hours of the day are divided into two periods of 12 hours, "am" and "pm".
AM is short for ante meridiem, Latin for "before noon". This is used to define hours of the day: "The meeting starts at 9 am." The opposite of am is PM, which is short for post meridiem, Latin for "after noon". This is used to define hours of the day: "The meeting ends at 5 pm."
The topic of whether 12:00 AM and 12:00 PM each corrospond to noon or midnight is a source of great confusion and pedantic argument. Often, it is better just to say "noon" or "midnight", and avoid the issue completely. Resolving this issue is one of the reasons for the creation of the 24-hour clock. In the United States, comfusingly 12:00 AM typically refers to midnight and 12:00 PM reffers to noon. This makes it so that the cycle of hours is
- 1:00 AM
- 2:00 AM
- ...
- 11:00 AM
- 12:00 PM
- 1:00 PM
- ...
- 11:00 PM
- 12:00 AM
- 1:00 AM
etc.
Another way of resolving the problem is to avoid referring to these tricky times entirely, and refer to times that are "just off" and therefore unambiguous such as 11:59 pm, or 00:01 am. Resolving this issue is one of the reasons for the creation of the 24-hour clock, sometimes called military time.