Definition of triploid in US English:



  • 1(of a cell or nucleus) containing three homologous sets of chromosomes.

    • ‘The triploid endosperm nucleus is derived from the fusion of two polar nuclei from the female parent and one sperm nucleus from the male.’
    • ‘The complete set of chromosomes has been duplicated in triploid and tetraploid nuclei.’
    • ‘In this type of endosperm, which is the most common in cereals, development starts with several rounds of divisions of the triploid nucleus without cytokinesis.’
    • ‘The first stage, grain enlargement, involves early, rapid division of the zygote and triploid nucleus.’
    • ‘At this stage the triploid endosperm nuclei are approximately the same size as the diploid nuclei of the pericarp and nucellus.’
    1. 1.1 (of an organism or species) composed of triploid cells.
      • ‘In humans, 10% of spontaneous miscarriages are due to triploidy, but triploids of fish and amphibians can grow to adults and some species are even fixed in the triploid state.’
      • ‘So-called triploid fish are unable to reach maturity and so are unable to breed.’
      • ‘Two samples from the original data set were omitted because one was from a triploid plant and the other from a tetraploid.’
      • ‘Long-term plans allow for the stocking of triploid grass carp, as well as dredging deeper holes and boat lanes.’
      • ‘The endosperm, a result of double fertilization in flowering plants, is a triploid tissue whose genetic composition is more complex than diploid tissue.’


  • A triploid organism, variety, or species.

    • ‘In contrast the data do suggest that gene transcript level in the hybrid triploids is related to genomic dosage.’
    • ‘Moreover, the high loads of inviable or weak aneuploid pollen produced by triploids induce high selfing rates in normally self-incompatible sexual diploids.’
    • ‘The populations showed continuous morphological variation connecting the species, but karyotypically they consisted of only three types of plants: diploids, triploids, and tetraploids.’
    • ‘Little is known about the transition from diploidy to polyploidy but in some species, triploids are thought to function as intermediates in this transition.’
    • ‘In triploids, three separate haploid chromosome sets have been observed, as well as one diploid and one haploid set.’