AM Full Form: is Ante Meridiem and PM Full Form: is Post Meridiem. AM represents as Anti Meridiem which means "before midday" and PM represent as Post Meridiem which means "after midday". The 24 hours of the day are divided into two periods AM and PM. These both are Latin words used in 12-hour clock system to represent 'Before Noon' and 'After Noon'. They also represented as A.M. and P.M.
Both AM and PM are used to differentiate the time of the day and night in a 12-hour time zone. The first 12-hour duration runs from midnight to noon from (12 am to 12 pm) and is known as AM. The second 12-hour duration runs from noon to midnight from (12 pm to 12 am) and is known as PM. So, in simple first 12-hour is A.M (midnight) and the second 12-hour is PM (Afternoon).
For Example: If I would say, I will come at 8 O'clock so it may be confusing that it is in the morning or evening. To remove this confusion, we used AM and PM.
There are also some other full form of am and pm mostly used but depend on a particular topic, given in the below.
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