- a combining form borrowed from Latin, meaning “half,” freely prefixed to English words of any origin, now sometimes with the senses “partially,” “incompletely,” “somewhat”: semiautomatic; semidetached; semimonthly; semisophisticated.
- a semidetached house
- short for semifinal
- US, Canadian, Australian and NZ short for semitrailer
- half
- partially, partly, not completely, or almost
- occurring twice in a specified period of time
