Aa

a.m. (ante meridiem) Definition:The abbreviation a.m. stands for ante meridiem, a Latin phrase meaning “before midday.” It is used to show times between midnight (12:00 a.m.) and just before noon (11:59 a.m.) on a 12-hour clock. Example: Tip:Think of a.m. as “at morning” to help remember that it covers the morning hours.