AMPM

ampm, commonly written as a.m. and p.m., denotes the two halves of the day on the 12-hour clock. The terms ante meridiem ('before noon') and post meridiem ('after noon') come from Latin and were adopted into English timekeeping to distinguish morning hours from afternoon and evening hours. On a 12-hour clock, a.m. spans from 12:00 midnight to 11:59 a.m., while p.m. spans from 12:00 noon to 11:59 p.m.

Different punctuation styles exist: some style guides use a.m. and p.m. with periods, others use am and pm without periods, and many digital interfaces display AM or PM in uppercase. A common point of confusion is the designation for 12:00. By convention, 12:00 a.m. is midnight and 12:00 p.m. is noon.

In addition to time notation, AMPM is the name of a chain of convenience stores in the United States. The brand, associated with BP, operates retail outlets that offer fuel, snacks, and beverages, often in conjunction with gas service, primarily in the western United States.

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