What is full form of AM?

Answer 1

ante meridian {A.M.}

post meridian {P.M}

By definition, 12 A.M. denotes midnight, and 12 P.M. denotes noon, but there is sufficient confusion over these uses to make it advisable to use 12 noon and 12 midnight where clarity is required.

ankit rane

Guna(m.p)

Answer 2

The abbreviations AM and PM represent the Latin phrases ante/post meridiem, which mean 'before/after midday'. They have been in use in English since the 17th century.