Hirudinea
noun plural
Hir·u·din·ea
| \ ˌhir-(y)ə-ˈdin-ē-ə
\
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Medical Definition of Hirudinea
: a class of hermaphroditic aquatic, terrestrial, or parasitic annelid worms distinguished by a coelom nearly obliterated by connective tissue and reduced to a series of vascular sinuses, by modification of the hindmost segments into a sucking disk, and by the absence of parapodia and setae