a.m.
adverbadjectivecommon in dialogue
- United States
In the 12-hour period from midnight to noon (the first half of the day) when using the 12-hour clock.
adverb
- 1
In the 12-hour period from midnight to noon (the first half of the day) when using the 12-hour clock.
Greenfield … Monday thru Friday, 9 to 12 a.m.
One of the most common night shifts is the 12 a.m.-to-8 a.m. shift.
We never say 12 a.m. or 12 p.m. It's either 12 midnight or 12 noon, respectively.
The 12-hour clock uses A.M. for the morning hours of midnight (12:00 A.M.) to almost noon (11:59 A.M.) and the P.M. designation for the hours from noon (12:00 P.M.) to almost midnight (11:59 PM).
Etymology
Abbreviation of ante meridiem (“before noon”).
adjective
- 1
Variant of ad modumInitialism of ad modum.
a.m. · In the 12-hour period from midnight to noon (the first half of the day) when using the 12-hour clock.
aa · A form of lava flow associated with Hawaiian-type volcanoes,…Aa · Several waterways in Europe. A river in northern France,…AA · A member of Alcoholics Anonymous.