AM and PM Full Form
What is the full form of AM and PM?
AM and PM stands for Ante meridiem and Prime Meridiem respectively in a 12-hr time system A 12 hr clock is a system for time convention used in most analog and digital clocks.24 hrs in a day is divided into two time zones of 12 hr each. AM or Ante Meridiem means before Midday(midnight to noon) and PM or Prime Meridian means after Midday(noon to midnight). Each day has 24 hours, each hour consists of 60 minutes, and each minute consists of 60 seconds. The 12 hr clock is also called the AM-PM clock.12-hour clock system is followed in many countries around the world including the United states of America,India and parts of the British Empire.
What is Meridiem?
The time when the sun is exactly above the reference meridian, that will be considered as meridien with reference to that meridian.So, meridiem refers to midday,ante meridiem, before the meridian, and post meridiem, after the meridian.
The time in different regions is calculated based on an imaginary longitudinal line called Meridian,it divides earth into equal halves,east and west hemispheres and the time is based on position of the Sun and the moon with respect to the meridian. Since, Earlier days time was measured by using sun positions. Each day is divided into 2 cycles. One cycle is tracked by the position of the sun and the other by the moon;Noon is the time when the sun reaches the meridian longitude point and is therefore used as a standard for calculation of time.
History of AM and PM
The 12-hr clock system was used in mesopotamian and Egyptian civilizations. Sundials were widely used those days. Romans also used a 12-hr system. Egyptians used sun-dial clocks for daytime use and Egyptian water clocks for night-time, these were recovered from pyramids of pharaohs.
Where does this name come from?
These are Latin words ‘Meri’ means ‘Mid’ and ‘diem’ means ‘day’. ‘Anti’ means ‘before’ and ‘post’ means ‘after’.Thus, AM means ‘Before midday’ and ‘Post’ means ‘After midday’.
What is Ante-Meridiem?
Ante Meridiem means ‘before midday’. Here the position of the sun will be before the meridian.The time from midnight of one day to the midday of next is AM.
What is Post Meridiem?
Post meridiem means ‘before meridiem’.Here the sun will be after the meridian longitude position. The time cycle from one midday (noon) to mid-night of the next day.
What is the difference between 12 hr and 24 hr clock?
A 24 hour clock is based on the convention that time is calculated from midnight of one day to midnight of second day.A 12 hr clock splits this time to 2 cycles of 12 hr each and denoted by AM and PM.
Which are the countries that use the 12 hr clock system?
Most of the countries use this system.Australia,Bangladesh,Canada, Colombia, Egypt, El Salvador, Honduras, India, Ireland, Jordan, Malaysia, Mexico, New Zealand, Nicaragua, Pakistan, Philippines, Saudi Arabia and the U.S uses a 12-hr clock system. Military and Government services usually use 24hr clock.
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Frequently Asked Questions (FAQs)
AM stands for Ante-meridiem before midday.
PM stands for Prime Meridiem or After-Midday
USA, India, Canada, Egypt etc are few countries that follow 12 hr clock or AM-PM Clock.
The SI unit of time is seconds.The 24hr clock and 12 hr clock which is also called the AM-PM clock is used in measuring time.
AM denotes time from 12 am midnight to the next day 11:59:59 am midnoon. While PM denotes time from 12 pm afternoon to 11:59:59 pm midnight.The 12 a.m and 12pm usage cause confusion in users.