In Canaa and the United States, the term military time is a synonym for the 24-hour clock notation, which counts the hours of the day from 00 to 23. In these regions, the time of day is customarily given almost exclusively using the 12-hour clock notation, which counts the hours of the day as 12, 1, ..., 11 with suffixes 'a.m.' and 'p.m.' distinguishing the two diurnal repetitions of this sequence. The 24-hour clock is commonly known there only in a few specialist areas (military, aviation, navigation, meteorology, astronomy, computing, logistics, emergency services, hospitals), where the ambiguities of the 12-hour notation are deemed too inconvenient, cumbersome, or outright dangerous, with the military's use being historically the first and most famous example. The term "military time" has no particular meaning in most other regions of the world, where the 24-hour clock has long become a common element of every-day civilian life.