POLYPLOID
Polyploid organism, cell or nucleus, unlike haploid or diploid organism, cell or nucleus, contains more than two haploid sets of chromosomes. Haploid set of chromosomes contains one copy of each autosome (all chromosomes, except sex chromosomes) and one sex chromosome. Haploid number of chromosomes (n) is a characteristic feature of a gamete. Let us denote the whole totality of autosomes by A, one sex chromosome by X, and the other one by Y, then n = A + X = A + Y. Triploid set of chromosomes contains three (3n) haploid sets, tetraploid has four (4n) of them, pentaploid consists of five (5n) haploid chromosome sets, etc.