Semi

How to spell semi

4 letters · 2 syllables

How to pronounce semi

Say the part in capitals loudest.

What does semi mean?

1. nounA semi-detached house; one of a pair of houses joined by a shared wall.
2. nounA large articulated lorry consisting of a tractor unit and a semi-trailer.
3. nounA semifinal; a match or round immediately before the final.

Semi in a sentence

• They bought a three-bedroom semi on a quiet suburban street.

• A semi jackknifed across two lanes during the storm.

• The team reached the semi but lost on penalties.

• The couple sold their semi and moved into a detached property.

• The driver parked the semi at the truck stop overnight.

• Tickets for the semi sold out within an hour.

Where does semi come from?

Language of origin: Latin

This little word is the Latin prefix semi, meaning literally 'half', standing on its own as a noun. In Latin semi attached to countless words to halve their meaning, much as it still does in English in 'semicircle' and 'semifinal'. By the late nineteenth and twentieth centuries English speakers began clipping longer compounds down to just the prefix: a 'semi-detached house' became a 'semi', and a 'semi-trailer truck' likewise became a 'semi'. The same root sits behind 'sesqui' and a whole family of fraction words, and it is distantly related to the Sanskrit and Greek terms for 'half'. Because the spelling is short and entirely phonetic, the only real point to remember is that it ends in a single 'i', not a 'y' or 'ie'.

How the word is built

• semi- (from Latin semi: half), used here as a standalone clipped noun