time counting system, divided into two parts: AM and PM
exeter cathedral astronomical clock
The 12-hour clock is a time convention in which the 24 hours of the day are divided into two periods: a.m. (from Latin ante meridiem, translating to "before midday") and p.m. (from … Wikipedia
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Wikipedia
en.wikipedia.org › wiki › 12-hour_clock
12-hour clock - Wikipedia
2 weeks ago - This eventually evolved into the two 12-hour periods which are used today, one called "a.m." starting at midnight and another called "p.m." starting at noon. The 12-hour clock can be traced back as far as Mesopotamia and ancient Egypt. Both an Egyptian sundial for daytime use and an Egyptian water clock for night-time use were found in the tomb of Pharaoh Amenhotep I.
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TimeAndDate
timeanddate.com › time zones › am and pm
AM and PM: What Do They Mean?
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, 1 am is one hour after midnight, and 5 am is early in the morning; 5 pm is late in the afternoon, while 11 pm is one ...
Discussions

the difference between 12:30am and 12:30pm
Please help me to understand the difference between 12:30am and 12:30pm, when it's after noon? Is it late afternoon? How to remember? More on preply.com
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4
December 10, 2020
Is 12 PM at noon? How is that when 11 am is in the morning And 1 am is in the night. Where did the 12 am go?
12pm is noon, 12am is midnight. More on reddit.com
🌐 r/EnglishLearning
156
96
October 10, 2024
What time is "afternoon" and when is "evening" ?
The difference between afternoon and evening can sometimes be a bit confusing but more-or-less follows these rules. Howe More on en.amazingtalker.com
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If 12 AM is midnight, why is 12 PM noon? Shouldn’t “AM” stand for after midnight and “PM” after morning?
AM stands for "ante meridiem", which means "before midday" and PM stands for "post meridiem", meaning "after midday." More on reddit.com
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May 20, 2025
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NPL
npl.co.uk › resources › q-a › is-midnight-12am-or-12pm
Midnight - is it 12am or 12pm? - NPL
There are no official standards established for the meaning of 12am and 12pm, but it is generally accepted that 12am means midnight and 12pm means midday. The ‘am’ and ‘pm’ stand for ante meridiem and post meridiem – Latin words meaning ...
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EnglishClub
englishclub.com › efl › articles › vocabulary › 12am-12pm-whats-the-difference
12am & 12pm – What’s the Difference?! | EnglishClub
Meridian = 12 noon 12:01pm is in the afternoon – 1 minute past noon. 12:01am is in the night before noon arrives (except in extreme latitudes when it could still be during the day in summer months – which is a good enough reason to use the 24 hour clock, wherein there is no confusion between ...
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Royal Museums Greenwich
rmg.co.uk › stories › time › noon-12-am-or-12-pm
Is noon 12 am or 12 pm? | Royal Museums Greenwich
Well, maybe not, especially if you're using a 12-hour clock. When most people say 12pm, typically they're talking about the middle of the day: 12 noon. When they say 12am, they normally mean 12 midnight.
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Wikipedia
en.wikipedia.org › wiki › Midnight
Midnight - Wikipedia
19 hours ago - The US National Institute of Standards and Technology (NIST) recommends avoiding confusion altogether by using "11:59 pm" or "12:01 am" and the intended date instead of "midnight" or "12:00 am".
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Quora
quora.com › What-time-is-12-00-am-night-or-morning
What time is 12:00 am night or morning? - Quora
Answer (1 of 10): Technically there is no 12:00 AM, its either midnight or noon. Because 12:00:00.001 or immediately thereafter is AM, most computer time logging and entry will consider and display midnight as AM.
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Eileen's Lounge
eileenslounge.com › viewtopic.php
What time is 12 PM - Eileen's Lounge
Since PM means after noon, I guess it's probably midnight, but I'm really not sure because clearly 12 AM would also have to be midnight from the same logic! ... 12 pm is midday (Noon). Think of it this way. 11:59 is that last time of the "morning." So, the next minute (12:00) is the beginning ...
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Preply
preply.com › home › english › the difference between 12:30am and 12:30pm
the difference between 12:30am and 12:30pm | Learn English
Okay so when do we say 12:30 AM? So it's in the first period which begins at midnight. So technically, 12AM and 12:30PM is just afternoon, which technically is 12PM. So to avoid confusion, many people do not use 12AM or 12PM, and prefer to use midnight for 12AM and noon for 12PM.
Published   December 10, 2020
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Timewatch
timewatch.com › home › am pm explained. is noon 12am or 12pm? why are there 24 hours in a day?
AM PM explained. Is noon 12AM or 12PM? Why are there 24 hours in a day?
October 31, 2025 - According to the Royal Observatory in Greenwich, London, (this is where Greenwich Mean Time or GMT originates) at exactly 12 noon, the Sun is at its highest point in the sky and directly over the meridian.
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The Guardian
theguardian.com › notesandqueries › query › 0,,-1752,00.html
Is midnight 12pm or 12am? | Notes and Queries | guardian.co.uk
Skip to main content · EITHER, since it is both 12 hours before and after noon. The real question is: what is mid-day
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Encyclopedia Britannica
britannica.com › technology › engineering › mechanical engineering
What Do AM and PM Stand For? | Time, Clock, History, & Facts | Britannica
1 week ago - However, it’s important to be clear when communicating times to avoid misunderstandings, particularly around the ambiguous 12:00 hours. When am or pm are omitted, time expressions such as “in the morning,” “in the afternoon,” or “at ...
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Cuemath
cuemath.com › measurement › am-pm
AM and PM - Meaning, Full Form of AM PM | Relation with 24-Hour clock
At this time of the day, the Sun is directly over the meridian and that is the reason why it is neither AM nor PM. The same rule applies to 12 midnight, which is also neither AM nor PM. However, technically, 12 noon refers to the time of the afternoon when the sun is overhead.
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Encyclopedia Britannica
britannica.com › dictionary › eb › qa › parts-of-the-day-early-morning-late-morning-etc
Parts of the Day: Early morning, late morning, etc. | Britannica Dictionary
Late morning 11 am to 12pm · Afternoon 12 pm to 5 pm · Early afternoon 1 to 3pm · Late afternoon 4 to 5pm · Evening 5 pm to 9 pm · Early evening 5 to 7 pm · Night 9 pm to 4 am · I hope this helps.
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Quora
quora.com › What-is-12-am-and-12-pm
What is 12 am and 12 pm.? - Quora
It is exactly ON the meridian. So what should 12 mean? So now some clocks MIGHT show a time as 12:45 PM instead of 00:45 PM but neither of these are ambiguous. It is clear that both are in the afternoon.
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Quora
quora.com › Is-12pm-noon-or-midnight
Is 12pm noon or midnight? - Quora
Answer (1 of 20): By convention, 12:00 PM is noon while 12:00 AM is midnight. What’s following is purely informative and you can skip it if you only want an direct answer. Outside of the view on a 12 hours clock, this can be confusing for anyone who think to follow the logical numerical sequenc...
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QuillBot
quillbot.com › home › is 12 p.m. afternoon?
Is 12 p.m. afternoon?
December 16, 2024 - 12 p.m. is the start of the afternoon. It comes one minute after 11:59 a.m. and is expressed as 12:00 in 24-hour clock.
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AmazingTalker
en.amazingtalker.com › questions › 1158
What time is "afternoon" and when is "evening" ?
The afternoon is the time between 1 to 5 pm, the Evening is the part between 5 to 7 pm, and Night is the time from 9 to 4 pm.