polyploid /pol″əploid/ [Gk, polys + plous, times] , 1. n., an individual, organism, strain, or cell that has more than twice the haploid number of chromosomes characteristic of the species. The multiple of the haploid number is denoted by the appropriate prefix, as in triploid, tetraploid, pentaploid, hexaploid, heptaploid, octaploid, and so on. Polyploidy is rare in animals, producing individuals that are abnormal in appearance and usually infertile. It is common in plants, however; such plants generally are larger, have larger cells, and are hardier than diploid plants. 2. adj., pertaining to such an individual, organism, strain, or cell. Also called polyploidic. Compare aneuploid. −polyploidy, n.
