A micro is a small computer. The word is a short form of microcomputer, and it was common in the 1970s and 1980s, especially in Britain, when computers first came into homes and schools — the BBC Micro is the famous school machine. People said “a micro” the way we now say “a computer” or “a laptop.” Today the noun sounds dated; if you use it, you are usually talking about that older kind of machine, or speaking in an old-fashioned British way. Though actually, micro is busy elsewhere in English: as a prefix it means “very small” (microscope, microbe, microwave), and people sometimes clip other micro- words too. This entry is only the small computer.