Definition of ante meridiem in English:

ante meridiem

adverb

  • Before midday; applied to the hours between midnight and the following noon. Usually abbreviated a.m., a.m., or am.

Origin

Mid 16th century; earliest use found in John Dee (1527–1609), mathematician, astrologer, and antiquary. From classical Latin ante merīdiem before midday from ante before + merīdiem, accusative of merīdiēs noon.

Pronunciation

ante meridiem

/ˌanti mɪˈrɪdɪəm//ˌanteɪ mɪˈrɪdɪəm/