noun. a condition wherein a homologous couple of chromosomes is accompanied by an extra matching chromosome inside each cell nucleus.

TRISOMY: "Trisomy is the elicitor of many disorders, inclusive of down syndrome, wherein there are three copies of chromosome 21. "
Cite this page: N., Pam M.S., "TRISOMY," in, April 29, 2013, (accessed April 9, 2020).