cytotaxonomy \cy`to*tax*on"o*my\ (s[imac]`t[-o]*t[a^]ks*[o^]n"[-o]*m[y^]), n. (Biology) A branch of taxonomy which uses the characteristics of cellular structures, such as somatic chromosomes, to classify organisms. [PJC] -- {cy`to*tax*on"o*mist}, n. -- {cy`to*tax`o*nom"ic}, a. -- {cy`to*tax`o*nom"ic*al*ly}, adv. [PJC]