n.
Pronunciation: ˌ ad-v ə n- ' ti-sh ə , -( ˌ )ven-
Function: noun
Etymology: New Latin, alteration of Latin adventicia, neuter plural of adventicius coming from outside, from adventus, past participle
Date: 1876
: an external chiefly connective tissue covering of an organ especially : the external coat of a blood vessel
– ad · ven · ti · tial \ -sh ə l \ adjective