Latin post meridiem

Using numbers from 1 to 12, followed by am or pm, the 12-hour clock system identifies all 24 hours of the day. For example, 5 am is early in the morning, and 5 pm is late in the afternoon; 1 am is one hour after midnight, while 11 pm is one hour before midnight.

Why do we use the a.m.-p.m. system for telling time? Early mechanical clocks showed all 24 hours, but over time, clockmakers found the 12-hour system simpler and cheaper. Of course, a.m. stands for ante meridiem, which is Latin for “before midday.” And p.m. means post meridiem — “after midday.”

Noon (or midday) is 12 o’clock in the daytime. It is written as 12 noon, 12 p.m. (for post meridiem, literally “after noon”), 12 pm, or 12:00 (using a 24-hour clock). Solar noon is the time when the Sun appears to contact the local celestial meridian.

There is no such time as 12:00pm Their reasoning was thus: pm stands for Latin post meridiem, usually translated in English as “after midday”. As midday is meridiem — that is, midday, the mid-point around which the other times are ordered — it cannot be said to be post itself. Therefore, 12:00pm is not a real time.

Midday and midnight conventions There are no standards established for the meaning of 12am and 12pm. It is often said that 12am Monday is midnight on Monday morning and 12pm is midday. This puts all the times beginning with 12 and ending with am in the same one-hour block, similarly with those ending with pm.

The American Heritage Dictionary of the English Language states “By convention, 12 AM denotes midnight and 12 PM denotes noon. Because of the potential for confusion, it is advisable to use 12 noon and 12 midnight.”

The abbreviation am stands for ante-meridiem (before the Sun has crossed the meridian line), and pm stands for post-meridiem (after the Sun has crossed the meridian line). At 12 noon, the Sun is at its highest point in the sky and directly over the meridian.

Midnight is exactly 180 degrees apart from noon because the earth is round in the network of geographical coordinates the meridian of Greenwich indicated 12:00 noon Any point on the surface of planet earth at 180 degrees of the meridian of Greenwich or “0” is marking midnight this means that it is neither am nor pm.

If you want to set up a meeting that starts at noon, you would set it to start at 12 PM. If you would like to set up a meeting to start at midnight, it would start at 12 AM.

The abbreviations a.m. and p.m. stand for the Latin ante meridiem and post meridiem, meaning before and after midday.

AM stands in short for Ante Meridiem, de latin name for “Before Midday” or “Before Noon”. An example: 10.00 a.m. is 10 o-clock in the morning. PM stands in short for Post Meridiem, de latin name for “After Midday” or “After Noon”. An example: 10.00 p.m. is 10 o-clock in the evening.

12-hour clock

Midnight is 00:00 am. “Monday Midnight”, or, more accurately, ‘midnight on Monday’, is that time which occurs one minute after “11:59 PM Monday” and is, in fact, 00:00 am on Tuesday morning. All time after Midnight 00:00 is Monday morning (during the 1st, 12 hours of a 12 hour clock and 24 hour day).

12 noon can be neither 12 am (in English before noon) nor 12 pm (after noon). It is simply noon.

Time. There is no space between the number and the am/pm definer. Do not use full stops in ‘am’ or ‘pm’. Use a full stop rather than a colon to separate the minutes from the hours.

Lowercase a.m. and p.m. and always use periods. Lowercase noon and midnight. Do not use 12 p.m. or 12 a.m. Use noon or midnight.

In addition, when writing the times 1:00 pm, 2:00 pm, etc., it is perfectly acceptable to omit the zeroes and write 1 pm, 2 pm, instead. Finally, note that while in the US we use a 12-hour clock, some countries use a 24-hour clock, or military time.

It is now rare to see periods placed after these abbreviations as in “A.M.”; but in formal writing it is still preferable to capitalize them, though the lower-case “am” and “pm” are now so popular they are not likely to get you into trouble. …

Technically speaking, 6 p.m. should probably be considered the most formal option. However, it is common practice to omit the punctuation nowadays and simply write 6 pm. I would not recommend omitting the space between the number and ‘pm’. You can simply write 6 in more informal situations.