semi

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.

Origin of semi-

Middle English <Latin sēmi-; cognate with Old English sōm-, sām- half (modern dial. sam-), Old High German sāmi-,Sanskrit sāmi-,Greek hēmi-;cf. sesqui-

words often confused with semi-

See bi-¹.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

How to use semi in a sentence

Here they are semi-touching at a grocery store; she likes kombucha.
All Your Internet Boyfriends Are Taken: Gosling, Cumberbatch, and now Joseph Gordon-Levitt|Melissa Leon|January 3, 2015|DAILY BEAST
Brinsley stepped up to the passenger side of the patrol car, raised a silver Taurus semi-automatic pistol and began firing.
'Please Don't Die!': The Frantic Battle to Save Murdered Cops|Michael Daly|December 22, 2014|DAILY BEAST
Tiger Lily and her tribe, however, were outfitted in semi-realistic outfits (read: nearly naked).
‘Peter Pan Live!’ Review: No Amount of Clapping Brings It to Life|Kevin Fallon|December 5, 2014|DAILY BEAST
For the next hour and half I was the willing sex slave of a semi-professional Master I had met through a friend.
Whip It: Secrets of a Dominatrix|Justin Jones|November 25, 2014|DAILY BEAST

After curing the elderly of their semi-suicidal depression, winning the White House must seem like a snap.
Ben Carson’s Bizarrely Serious, Seriously Bizarre Campaign Crew|Olivia Nuzzi|November 12, 2014|DAILY BEAST
Our troops have done all that flesh and blood can do against semi-permanent works, and they are not able to carry them.
Gallipoli Diary, Volume I|Ian Hamilton
The stop-keys will be seen arranged in an inclined semi-circle overhanging and just above the keyboards.
The Recent Revolution in Organ Building|George Laing Miller
There are four types: bituminous (soft), anthracite (hard), semi-bituminous and semi-anthracite.
Hallowed Heritage: The Life of Virginia|Dorothy M. Torpey
There were semi-savage native chiefs, and there were others, like Aguinaldo himself, with humane instincts.
The Philippine Islands|John Foreman
The brilliant light of a policeman's torch sliced through the semi-darkness and spotted him.
Hooded Detective, Volume III No. 2, January, 1942|Various

British Dictionary definitions for semi (1 of 2)

semi

/ (ˈsɛmɪ) /

noun plural semis

British a semidetached house

short for semifinal

US, Canadian, Australian and NZ short for semitrailer

British Dictionary definitions for semi (2 of 2)

semi-

prefix

halfsemicircle Compare demi- (def. 1), hemi-

partially, partly, not completely, or almostsemiprofessional; semifinal

occurring twice in a specified period of timesemiannual; semiweekly

Word Origin for semi-

from Latin; compare Old English sōm-, sām- half, Greek hēmi-

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for semi

semi-

pref.

Half:semicanal.

Partial; partially:semiconscious.

Resembling or having some of the characteristics of:semilunar.

Scientific definitions for semi

semi-

A prefix that means half, (as in semicircle, half a circle) or partly, somewhat, less than fully, (as in semiconscious, partly conscious).

semi

Origin of semi

Other definitions for semi (2 of 2)

Origin of semi-

words often confused with semi-

Words related to semi

How to use semi in a sentence

British Dictionary definitions for semi (1 of 2)

British Dictionary definitions for semi (2 of 2)

Word Origin for semi-

Medical definitions for semi

Scientific definitions for semi