Semi- is a Latin prefix to a verb, noun, or adjective meaning "half". Some compounds formed with it are often abbreviated to simply "semi" in appropriate contexts:

  • Semi or semis, in financial news, often used to refer to the semiconductor industry or the corporations therein
  • Semi-automatic firearm
  • Semi-detached house, a type of housing
  • Semi-final, of a knockout competition
  • Semi-formal, (esp. high school) dance
  • Semi-submersible, a watercraft
  • Semi-trailer truck (UK: articulated lorry)
  • Semiquaver, the time interval in music, which is half the length of a quaver
See also
  • Semiconductor Equipment and Materials International (SEMI)