The Collaborative International Dictionary
Heterochronism
Heterochronism \Het`er*och"ro*nism\, Heterochrony \Het`er*och"ro*ny\, n. [Gr. ? of different times; ? other + ? time.] (Biol.) In evolution, a deviation from the typical sequence in the formation of organs or parts.
Wiktionary
heterochronism
n. (context biology English) heterochrony