Military time is used by the U.S. military, as well as most of the world. Military time is a way of reading a clock on a 24-hour system instead of the standard two 12-hour systems in a single day. The purpose of military time is to avoid confusion between a.m. and p.m. Only a few countries, including the United States and Canada, still use the 12-hour clock on a day-to-day basis.
Interesting fact:
The term "o'clock" comes from the French, "a la cloche", which means "at the bell." A long time ago, if people didn't have watches or clocks at home, they would rely on the bell ringing from the bell tower ... so it was said "It is nine "a la cloche" (at the bell) and over time it transformed into the English form "o'clock".
