Micro or Mikro, from the Greek  (), means "small". It can be used to indicate a smaller than average scale (microscopic scale), as opposed to prefixes mega and , which can be used to indicate a larger than average scale.

Micro- (symbol µ) is a unit prefix in the metric system denoting a factor of 10^-6 (one millionth). Confirmed in 1960, the prefix comes from the Greek  (), meaning "small".