What is "monomorphous"

Monomorphic \Mon`o*mor"phic\, Monomorphous \Mon`o*mor"phous\, a. [Mono- + Gr. morfh` form.] (Biol.) Having but a single form; retaining the same form throughout the various stages of development; of the same or of an essentially similar type of structure; -- opposed to dimorphic, trimorphic, and polymorphic.