hexaploid Syllabification: (hex·a·ploid)Pronunciation: /ˈheksəˌploid/ GeneticsDefinition of hexaploid adjective (of a cell or nucleus) containing six homologous sets of chromosomes. (of an organism or species) composed of hexaploid cells. noun a hexaploid organism, variety, or species. Derivatives hexaploidy noun hexaploid in other Oxford dictionaries Definition of hexaploid in the British & World English dictionary