Why do we say A.M. and P.M. when telling time?
The letters A.M (ante meridian) P.M (post meridian) tell us what part of the day it is on a 12 hour clock.
As we all know, there are 24 hours in a day but only 12 hour numbers on a clock. This is because in most countries the hours of the day are usually divided into two parts for timekeeping.
We call the first part of the day a.m. and the second part p.m.
The first clued clocks did not keep good time. They had to be set every day at noon, when the sun was at the meridian, or the highest point in the sky.
From this we began to call the morning part of the day a.m., meaning ”ante meridian.” or before noon. P.M. means “post meridian” or after noon.
If every town set its clocks by the sun today, few places would be on the same time. When it is noon in one town, it is not yet noon in a town a few miles east. For this reason. the world is divided into time zones. All the clocks in a time zone are set the same time. – Dick Rogers
- Posted in: Good Time
- Tagged: 12 Hour Clock, 12 Hour Numbers on a Clock, 24 Hours in a Day, Afternoon, Ante Meridian, Clock, Clock Time, Clocks, First Clued Clock, First Part of the Day A.M., Highest Point in the Sky, Letters A.M., Letters P.M., Meridian, Miles, Morning, Morning Part of the Day, Post Meridian, Second Part of the day P.M., Time, time dick, Time Zone, Time Zones, Timekeeping