a prefix occurring in loanwords from Greek, where it meant “two,” “twice,” “double” (diphthong); on this model, freely used in the formation of compound words (dicotyledon; dipolar) and in chemical terms (diatomic; disulfide).
English Affixes From A To Z: A One-Stop List Of Suffixes, Prefixes, and Combining FormsIn English, we love to make new words by adding all sorts of bits to the front and back of existing terms. These are called affixes, and they are added to the base or stem of a word. When attached to the end of word, the affix is called a suffix. And to the beginning? A prefix.
Definition for di- (2 of 3)
variant of dis-1 before b, d, l, m, n, r, s, v, and sometimes g and j: digest; divide.
Definition for di- (3 of 3)
variant of dia- before a vowel: diorama.
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British Dictionary definitions for di- (1 of 2)
twice; two; doubledicotyledon
- containing two specified atoms or groups of atomsdimethyl ether; carbon dioxide
- a nontechnical equivalent of bi- 1 (def. 5c)
Word Origin for di-
via Latin from Greek, from dis twice, double, related to duo two. Compare bi- 1
British Dictionary definitions for di- (2 of 2)
variant of dia- diopter
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
Medicine definitions for di-
Two; twice; double:dichromatic.
Containing two atoms, radicals, or groups:diiodide.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Science definitions for di-
A prefix that means two, twice, or double. It is used commonly in chemistry, as in dioxide, a compound having two oxygen atoms.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.