• synonyms


adjective Also hap·loi·dic.
  1. single; simple.
  2. Biology. pertaining to a single set of chromosomes.
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  1. Biology. an organism or cell having only one complete set of chromosomes, ordinarily half the normal diploid number.
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Origin of haploid

First recorded in 1905–10; hapl- + -oid
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for haploid

Historical Examples

  • Haploid (n) chromosome numbers were determined from cells in diakinesis, metaphase I, and metaphase II of meiosis.

    Neotropical Hylid Frogs, Genus Smilisca

    William E. Duellman

  • Each of these divides again by mitosis (the chromosomes splitting lengthwise), the half or haploid number remaining.

    Taboo and Genetics

    Melvin Moses Knight, Iva Lowther Peters, and Phyllis Mary Blanchard

  • The next stage is their separation to the haploid daughter-nuclei, which have resulted from the reduction process.

    Darwin and Modern Science

    A.C. Seward and Others

  • Technically the tissue-cells are said to contain the diploid number of chromosomes, the gametes the reduced or haploid number.

    Being Well-Born

    Michael F. Guyer

British Dictionary definitions for haploid


adjective also: haploidic
  1. (esp of gametes) having a single set of unpaired chromosomes
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  1. a haploid cell or organism
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Compare diploid
Derived Formshaploidy, noun

Word Origin

C20: from Greek haploeidēs single, from haplous single
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 haploid


1908, from German haploid (1905), from Greek haplos "single."

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Online Etymology Dictionary, © 2010 Douglas Harper

haploid in Medicine


  1. Having the same number of sets of chromosomes as a germ cell, or half the diploid number of a somatic cell. The haploid number (23 in humans) is the normal chromosome complement of germ cells.
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  1. A haploid organism or cell.
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Related formshaploi′dy (-loi′dē) n.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

haploid in Science


  1. Having a single set of each chromosome in a cell or cell nucleus. In most animals, only the gametes (reproductive cells) are haploid. Compare aneuploid diploid. See Note at mitosis.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.