What do am and PM mean after mobile time? The original 24-hour system, without these letters, changed to 12 hour system
Am = morning, before 12 noon
PM = afternoon, after 12 noon
Am and PM in the morning and afternoon
Am and PM are abbreviations in English. If they are more specific, how to write them,
a. M. = ante meridiem [Latin] am; before noon
p. M. = post meridiem [Latin] afternoon