Definition of diploid in US English:



  • 1(of a cell or nucleus) containing two complete sets of chromosomes, one from each parent.

    Compare with haploid
    • ‘Oocytes and sperm are haploid, with one set of chromosomes, whereas somatic cells are diploid, with two chromosomal sets.’
    • ‘An obvious question is whether the mat bias is absent in azygotic meiosis after homologous chromosomes have coexisted in diploid cells for many mitotic divisions.’
    • ‘We started the experiments described below by establishing large populations of diploid cells.’
    • ‘We performed a similar experiment using h/h diploid cells as the host.’
    • ‘However, to a low extent, viable spores can also be recovered from a very small population of homozygous diploid nuclei in an otherwise haploid plasmodium.’
    1. 1.1 (of an organism or part) composed of diploid cells.
      • ‘Note that copy numbers in tetraploids were slightly less than double those in respective diploid progenitors.’
      • ‘The practical application that is considered is the full-sib family of a diploid outbreeding species.’
      • ‘Currently, six major tetraploid races are recognized and their diploid progenitors have been identified.’
      • ‘We examined the genetics of hybrid incompatibility between two closely related diploid hermaphroditic plant species.’
      • ‘The compactness of rice and sorghum genomes is evident compared to barley and diploid wheat genomes.’


  • A diploid cell, organism, or species.

    • ‘Arabidopsis thaliana and many closely related species are diploids with relatively few recent gene duplications.’
    • ‘We conclude that the haploids had a greater frequency of mutant phenotypes than the diploids.’
    • ‘Previous work has calculated the covariance expected under autosomal inheritance in diploids and haploids.’
    • ‘The diploid ancestor could not be identified because among the South American diploids there were no species matching in the FISH or RFLP pattern of rDNA.’
    • ‘In diploids, sexual reproduction promotes both the segregation of alleles at the same locus and the recombination of alleles at different loci.’


Late 19th century: from Greek diplous ‘double’ + -oid.