In countries that do not use a 24-hour clock, ‘AM’ and ‘PM’ are used to distinguish the time of day. ‘AM’ starts at midnight (12:00 AM) and ends when the clock strikes noon. Noon is 12:00 PM, and the ‘PM’ time continues throughout the afternoon and evening until midnight.
Some major countries that use AM and PM are the U.S., the U.K., Australia, India, Pakistan, Malaysia, and the Philippines.
“Brad wakes up at 7:00 AM and eats his evening meal at 6:00 PM.”
AM means ante meridian which is used to signify Morning in relations to time telling.
"Why did you wake me up 6am in the morning?"
PM means post meridian which is used to signify Night time in relations to time telling.
"Let's meet later today. Say 7pm?"