An abnormality involving a chromosome number that is not an exact multiple of the haploid number (one chromosome set is incomplete)

Wiktionary Word definitions in Wiktionary
n. (context genetics English) The condition of being aneuploid; the state of possessing a chromosome number that is not an exact multiple of the haploid number of the organism in question.

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
abnormal number of chromosomes, 1934, from aneuploid (1931), Modern Latin, coined 1922 by G. Täckholm from an- (1) "not" + euploid , from Greek eu- "well, good" (see eu- ) + -ploid , from ploos "fold" (see -plus ) + -oid .

WordNet Word definitions in WordNet
n. an abnormality involving a chromosome number that is not an exact multiple of the haploid number (one chromosome set is incomplete)

Wikipedia Word definitions in Wikipedia
Aneuploidy is the presence of an abnormal number of chromosomes in a cell , for example when having 45 or 47 chromosomes when 46 is expected in a human cell. It does not include a difference of one or more complete sets of chromosomes , which is called ...