from The American Heritage® Dictionary of the English Language, 4th Edition

  • adj. Having the same number of sets of chromosomes as a germ cell or half as many as a somatic cell.
  • adj. Having a single set of chromosomes.
  • n. An organism having haploid cells.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. Of a cell having a single set of unpaired chromosomes, such as a gamete.
  • n. A cell which is haploid; an organism, such as a fungus, with haploid cells.

from the GNU version of the Collaborative International Dictionary of English

  • adj. having half the number of chromosomes normally present in somatic cells; having only one chromosome of each type, and therefore having only one complete set of genes; Contrasted with diploid and polyploid. See also diploid.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • adj. of a cell or organism having a single set of chromosomes
  • n. (genetics) an organism or cell having only one complete set of chromosomes


From Greek haplous, single; see sem-1 in Indo-European roots + -oid.
(American Heritage® Dictionary of the English Language, Fourth Edition)
haplo- + -oid (Wiktionary)


  • The gametes they produce are haploid, meaning that they contain only one of each chromosome pair.

    Population Genetics

  • The nucleus of sperm and eggs are haploid, meaning they only have half their normal compliment of genetic material, while somatic cell nuclei are diploid (it occurs to Sci that she's gonna have to explain meiosis some day ...).

    ScienceBlogs Channel : Life Science

  • Males are haploid; they have only one copy of the genome.


  • Daniel Smith: So selection would favor haploid reproduction?

    At What Level did this Evolve?

  • In environments where fast reproduction is important, haploid organisms can have an advantage.

    At What Level did this Evolve?

  • But because males are haploid (and assuming monandry), her sisters share 75% of her genes.

    At What Level did this Evolve?

  • As for “life starts at conception” — two haploid gametes, themselves “alive”, certainly a product of “life”, come together to form a diploid cell which eventually becomes whatever its DNA demands: a mouse, an elephant, a human, whatever.

    Matthew Yglesias » Too Hot for CBS

  • The significance of the “diploid” genome is that Levy and colleagues obtained sequence from both chromosomes in each pair, rather than settling for a composite “haploid” genome.

    The $1,000 Genome

  • The inferred chromosome numbers of these extinct species suggest that seven to nine is the primitive haploid chromosome number of angiosperms and that most angiosperms approximately 70 percent have polyploidy in their history.

    Junk DNA is still junk - The Panda's Thumb

  • By the genetic bonds and Mendelian Progression, by diploid dupes and haploid hopes, I order you to do my will!

    The Lives of Felix Gunderson


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