I. a.m. BrE AmE ( also am British English ) /ˌeɪ ˈem/
[ Date: 1700-1800 ; Language: Latin ; Origin: ante meridiem 'before noon' ]
(ante meridiem) used to talk about times that are after ↑ midnight but before ↑ midday ⇨ p.m. :
Work starts at 9 am.
II. am /m, əm; strong æm/ BrE AmE verb
[ Language: Old English ; Origin: eom ]
the first person singular of the present tense of the verb ↑ be