Telling Time: A.M. and P.M.

Date: 10/30/2001 at 20:21:56
From: Gabrielle Rivera
Subject: Telling time

What do the a.m. and the p.m. mean in time?

Date: 10/31/2001 at 17:06:01
From: Doctor Sarah
Subject: Re: Telling time

Hi Gabrielle - thanks for writing to Dr. Math.

A.M. = ante meridiem

P.M. = post meridiem

They're from the Latin:

   ante = before

   post = after

   meridiem = noon

The American Heritage Dictionary online says that:

   "By definition, 12 a.m. denotes midnight, and 12 p.m. denotes noon,   
   but there is sufficient confusion over these uses to make it 
   advisable to use 12 noon and 12 midnight where clarity is 
   required." 

- Doctor Sarah, The Math Forum
  http://mathforum.org/dr.math/