[het-er-uh-zahy-guh s]

adjective Biology.

having dissimilar pairs of genes for any hereditary characteristic.
of or relating to a heterozygote.

Also het·er·o·zy·got·ic [het-uh-roh-zahy-got-ik] /ˌhɛt ə roʊ zaɪˈgɒt ɪk/.

Origin of heterozygous

1900–05; hetero- + Greek zygós, adj. derivative of zygón yolk; see -ous
Related formshet·er·o·zy·gos·i·ty [het-uh-roh-zahy-gos-i-tee] /ˌhɛt ə roʊ zaɪˈgɒs ɪ ti/, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for heterozygous

Historical Examples of heterozygous

  • The female is heterozygous for a dominant factor (F) which is lacking in the male.


    Reginald Crundall Punnett

  • Since no "pinks" appeared the color is recessive, and the brother was not heterozygous for it.

  • Although the mother was fertilized by a normal male, every daughter is heterozygous for one or the other of the lethal factors.

  • This shows that the mother of the original high sex-ratio was heterozygous for a recessive sex-linked lethal.

  • This heterozygous bar female is always readily distinguishable from the normal, but can not always be separated from the pure bar.

British Dictionary definitions for heterozygous



genetics (of an organism) having different alleles for any one geneheterozygous for eye colour Compare homozygous
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 heterozygous

1889, from heterozygote, from hetero- + zygote.

Online Etymology Dictionary, © 2010 Douglas Harper

heterozygous in Medicine




Having different alleles at one or more corresponding chromosomal loci.
Of or relating to a heterozygote.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

heterozygous in Science



Relating to a cell that has two different alleles at corresponding positions on homologous chromosomes. Compare homozygous.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.