I. noun Usage: often attributive Etymology: amplitude modulation Date: 1940 a broadcasting system using amplitude modulation, II. abbreviation airmail, Air Medal, in the year of the world, ante meridiem, master of arts
AM
Meaning of AM in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012