AM and PM are the abbreviated terms for Ante meridiem and Post meridiem which means before noon or midday and afternoon or midday respectively. The initial 12-hour period which lasts from midnight to noon is designated with AM while the next 12-hour period which lasts from noon to midnight is designated with PM.

What is AM and PM in time?

From the Latin words meridies (midday), ante (before) and post (after), the term ante meridiem (a.m.) means before midday and post meridiem (p.m.) means after midday. ... E. G. Richards in his book Mapping Time provided a diagram in which 12 a.m. means noon and 12 p.m. means midnight.

Is morning 12 AM or PM?

'Noon' means 'midday' or 12 o'clock during the day. 'Midnight' refers to 12 o'clock (or 0:00) during the night. When using a 12-hour clock, 12 pm typically refers to noon and 12 am means midnight.