What does AM and PM stand for when talking about time?
151984
Ante Meridian and Post Meridian.
63299
AM Stands for Amplitude Modulation and FM Stands for frequency Modulation. So in AM radio, the amplitude of the waves are changed while in the FM the frequency of the waves is changed. \nHence when the over riding of the waves is done, in an FM radio it is done in such a way that the frequency changes and the amplitude remains the same while in the am radio it is the other way round. AM radios have a shorter range!!
1147769
10:00am to 5:00am, the confusing part doesn't come in until after 12:00pm (noon).  1:00pm is 1300, 2:00pm is 1400, etc.  Up to that point, just put a : before the last 2 digits.
1052806
1 PM\n\nThe Brits are 6 hours ahead of you.\n\nYour time is (GMT -6).
850049
A.M. means  ante meridiem, from Latin, literally "before midday" and P.M. means post meridiem, from Latin, literally "after midday."
751575
The 12-hour clock is a timekeeping convention in which the 24 hours of the day are divided into two periods called ante meridiem (a.m., Latin from most idiomatic to most literal "forenoon" "before noon", "before midday", "before the middle of the day", "before the meridian", and "before the middle day") and post meridiem (p.m., Latin for "afternoon", "after noon", etc.) Each period consists of 12 hours numbered 12 (acting as a zero), 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11. The a.m. period runs from midnight (inclusive) to just before noon (exclusive), while the p.m. period runs from noon (inclusive) to just before midnight (exclusive). The most common convention is to assign 12 a.m. to midnight and 12 p.m. to noon, defining both half days to have a closed (inclusive) beginning and open (exclusive) end.\n\n\nHistory and usage\nThe 12-hour clock originated in Egypt. However, the lengths of their hours varied seasonally, always with 12 hours from sunrise to sunset and 12 hours from sunset to sunrise, the hour beginning and ending each half-day (four hours each day) being a twilight hour. An Egyptian sundial for daylight use[1] and an Egyptian water clock for nighttime use found in the tomb of Pharaoh Amenhotep I,[2] both dating to c. 1500 BC, divided these periods into twelve hours each. The Romans also used a twelve-hour clock: the day was divided into twelve equal hours (of, thus, varying length throughout the year) and the night was divided into three watches.\n\nThe Romans numbered the morning hours originally in reverse: for example, "3 a.m.", or 3 hours ante meridiem meant "three hours before noon", compared to the modern meaning of "three hours after midnight".\n\nEarly medieval clock faces used the 12 hour numbering scheme (using Roman numerals), but showed both a.m. and p.m. sequences simultaneously. This is known as the Double-XII system, and can be seen on surviving medieval clock faces, such as those at Ottery St Mary, Wells, and Venice.\n\nToday, most analog clocks use the 12-hour clock dial, where the hour hand (shorter and sometimes thicker) commonly rotates once every 12 hours. These are used even in cultures where the 24-hour notation is otherwise preferred. Some 12-hour dials show the numbers 13 to 23 written inside the primary 1 to 12 ring.\n\nAlthough it has largely been replaced today by the 24-hour notation around the world, especially in written communication, the 12-hour notation with a.m./p.
284748
I think it's just a play on AM or FM. AM (amplitude modulation) and FM (frequency modulation) are known for being "radio terms", so they called it XM, probably because X has a "cool" connotation.
724699
7.00 o'clock\n\nxitos
448355
11 PM\n\n(Of the previous day)\n(3 hours earlier)
45472
"Seven minutes past" is short for "Seven minutes past the hour" or seven minutes after the last "o'clock" e.g. it's 10:30, someone asks, "At what time did we come in?"  you say, "About seven minutes past."  means you came in about 10:07.
213340
PST is -8:00 GMT\n\nPST= Pacific Standard Time\nGMT= Greenwich Mean Time
1143156
Day consist of 24 hrs. First 12 hrs AM and next 12 hrs PM. Our watch shows only 12 hrs. This is due to differentiate the morning and evening or day and night. so from midnight 1 to noon 12 we say it as AM and from noon 1 to midnight 12 we say as PM. \n\n“AM” stands for the Latin phrase Ante Meridiem —which means “before noon”—and “PM” stands for Post Meridiem : “after noon"\n\n\nAM and PM - What is Noon and Midnight?\n-----------------------------------------------------\nAM and PM start immediately after Midnight and Noon (Midday) respectively.\n\nThis means that 00:00 AM or 00:00 PM (or 12:00 AM and 12:00 PM) have no meaning.\n\nEvery day starts precisely at midnight and AM starts immediately after that point in time e.g. 00:00:01 AM (see also leap seconds)\n\nTo avoid confusion timetables, when scheduling around midnight, prefer to use either 23:59 or 00:01 to avoid confusion as to which day is being referred to.\n\nIt is after Noon that PM starts e.g. 00:00:01 PM (12:00:01)\n\nAM  abbreviation ante meridiem \n-----------------------------------------\n\nMain Entry: an·te me·ri·di·em\nPronunciation: \n"an-ti-m&-'ri-dE-&m, -dE-"em\nFunction: adjective\nEtymology: Latin\nDate: 1563\nMeaning: being before noon\nAbbreviation a.m. \n\n\nPM  abbreviation post meridiem\n-----------------------------------------\nMain Entry: post me·ri·di·em\nPronunciation:\n -m&-'ri-dE-&m, -"em\nFunction: adjective\nEtymology: Latin\nDate: 1647\nMeaning: being after noon\nAbbreviation p.m.
6419
2:04:46pm pacific standard time. its 24 hour time so if its above 12 minus twelve so 14 - 12 means 2 o'clock in the afternoon. -800 is minus 8 hours from grenich mean time or the international date line pst just means pacific standard time
192205
most of the time. Some people mean the daylight hours
281180
pacific standard time, in the east states it eastern standard time,, in the mid usa is mountian time
244387
They are abbreviations of Latin expressions.  Ante Meridian and Post Meridian.  Before and After Noon.
442086
2:33 am and 14:53 (2:53 p.m.) local time