It means "midday" or "noon." It's a dissimulation of "medius + dies" where" "Medius" is an adjective put in the locative case meaning "in the middle of", and "dies" is a (feminine) noun meaning "day."
The reason it ends in "-em" instead of "-ies" is not certain but is said to be variants found in various parts where Latin used to be spoken.
Source: Oxford Latin Dictionary - entry "Meridies -ei"
AM Stands for Ante Meridiem and PM stands for Post Meridiem.
AM stands for 'Ante Meridiem' (Latin for 'before midday') and PM stands for 'Post Meridiem' (Latin for 'after midday').
AM as in 10AM stands for "ante meridiem" (before midday). PM as in 10PM stands for "post meridiem" (after midday). Source: http://answers.yahoo.com/question/index?qid=20060820143609AAMUvNU (where Wikipedia is listed as the source)
The Latin word ante meridiem refers to "before noon" in English language.
Meridian is an imaginary arc on the Earth's surface from the North Pole to the South Pole that connects all locations running along it with a given longitude That is correct but COMPLETELY unrelated to this question. Meridiem is not the same as meridian. meridiem is latin for "mid-day" as in "post meridiem" or "after mid-day" AM stands for ante meridiem. Ante is latin for "before" or "prior to" (all you poker players out there now know why the forced bet at the beginning of the hand is called the ante :)
ante meridiem post meridiem
am stands for Ante Meridiem and pm for post Meridiem. Meridiem is the word used for noon.
Ante Meridiem and Post Meridiem
AM = ante meridiem and PM = post meridiem. AM Ante Meridiem Stands for Before Noon in Latin PM Post Meridiem Stands for After Noon in Latin
Meridiem is Latin for the middle of the day. Ante meridiem (AM) is Latin for before the middle of the day, and post meridiem (PM) is Latin for after the middle of the day.
A.M is Ante Meridiem P.M is Post Meridiem
AM and PM are abbreviations for ante meridiem and post meridiem mean before noon and after noon post meridiem or post meridian.
A.M. = ante meridiem P.M. = post meridiem.
That is latin
AM: Ante Meridiem; PM: Post Meridiem
'Ante meridiem', meaning 'before noon'.
AM Stands for Ante Meridiem and PM stands for Post Meridiem.