1) Ante meridiem 2) Before noon 3) Morning 4) Occurring before noon 1) Morning 
• (a.) Being before noon; in or pertaining to the forenoon. (Abbrev. a. m.)
An`te·me·rid'i·an adjective [ Latin antemeridianus ; ante + meridianus belonging to midday or noon. See Meridian .] Being before noon; in or pertaining to the forenoon. (Abbrev. adjective m. ) 
[adj] - before noon
antemeridian, antemeridiem (A.M.) 1. Of or belonging to the forenoon or 'morning'. 2. Before midday; applicable to the hours between midnight and the following noon.
adjective before noon
occurring before noon. · of or pertaining to the forenoon.