ˌadvənˈtish(ē)ə, -ˌven- noun
( -s )
Etymology: New Latin, alteration of Latin adventicia, neuter plural of adventicius coming from outside, from adventus + -icius -icious
: an external covering or investment of an organ chiefly derived from the surrounding connective tissue ; especially : the external coat or layer of a blood vessel consisting mostly of fibroelastic connective tissue