noun Automotive.

an internal-combustion engine having hemispherical combustion chambers.

Origin of hemi

shortening of hemi-head


a combining form meaning “half,” used in the formation of compound words: hemimorphic.

Origin of hemi-

< Greek hēmi- half; cognate with Latin sēmi- semi-
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for hemi

Historical Examples of hemi

  • Hemi” means “half,” so each half of the globe is called a “hemisphere.

    Where We Live

    Emilie Van Beil Jacobs

  • The whole is finally protected by a hemi 360spherical covering of moss, made into a sort of felt and lined with wax.

    The Insect World

    Louis Figuier

  • Fine fighters Hemi Nape and his boys, were and well they bore themselves, but alas!

  • Kauaka hei a Hemi taku pu, let not my gun be in the possession of Hemi.

    First Lessons in the Maori Language

    William Leonard Williams

British Dictionary definitions for hemi



halfhemicycle; hemisphere Compare demi- (def. 1), semi- (def. 1)

Word Origin for hemi-

from Latin, from 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

Word Origin and History for hemi


word-forming element meaning "half," from Greek hemi- "half," from PIE root *semi-, which is the source of Sanskrit sami, Latin semi- (see semi-), Old High German sami- "half," and Old English sam-, denoting a partial or imperfect condition (see sandblind).

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for hemi



The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for hemi


A prefix meaning “half,” as in hemisphere, half a sphere.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.