triploid

An organism, tissue, or cell that possesses three complete sets of chromosomes per nucleus. A triploid may arise from the fusion of a haploid and a diploid nucleus, or from the fusion of three haploid nuclei. Triploid organisms are normally infertile, since meiosis results in gametes that have more or less than the normal haploid number of chromosomes. The endosperm tissue of angiosperms is typically triploid (or pentaploid in some monocotyledons).