Am is the present-tense, first-person, singular form of the verb "to be", the copula of the English language.

In German, am is a contraction for the preposition and definite article "an dem". It is used in place names, similar to the English "upon", as in "Frankfurt am Main".

When used as abbreviations, A.M., AM, Am, and am may refer to:

Electrical engineering

• Amplitude modulation (AM), a modulation technique used primarily to transmit speech at radio frequencies (see AM radio)

Science

• Attometre (am), an SI measure of length (see orders of magnitude (length) for a list of objects on this scale)
• the chemical symbol for Americium (Am)

Computing

• the country-code top-level domain for Armenia (.am)
• a complexity class (AM) in computational complexity theory (see Arthur-Merlin protocol)
• an artificial intelligence program by Doug Lenat
• an abbreviation for away message

Politics

• in the United Kingdom, post-nominal letters signifying membership of the National Assembly for Wales or the London Assembly
• in Australia, post-nominal letters signifying a Member of the Order of Australia

Other

• Ante Meridiem (A.M. and AM), Latin for "before noon", used to disambiguate hours of the day when using the 12-hour clock system
• Anno Mundi, Latin for "in the year of the world" (see Anno Domini)
• Anno Martyrum, Latin for "in the year of the martyrs", used in the Coptic calendar
• Artium magister , New Latin for Master of Arts
• the ISO 3166-1 alpha-2 country code for Armenia (AM)
• the ISO 639 alpha-2 language code for Amharic (am)
• the International Air Transport Association (IATA) airline designator for Aeromexico (AM)
• the Association of American Railroads (AAR) reporting mark for Arkansas and Missouri Railroad (AM)
• Airmail
• Air Medal
• the malevolent supercomputer in the story I Have No Mouth and I Must Scream
• Internet Slang for away message