-shəs adjective
Etymology: Latin adventicius
1. : coming from another source : added or appended extrinsically and not sharing original, essential, and intrinsic nature : not inherent or innate
we distinguish between borrowed, adventitious energy in verse, and its natural energy — C.D.Lewis
a disengagement of its own proper ideas from the adventitious notions which have crept into it — A.N.Whitehead
the adventitious paraphernalia of 20th century living — Time
2. biology
a. : arising sporadically or in other than the usual location
an adventitious part in embryonic development
b. : occurring spontaneously or accidentally in a country or region to which it is not native
adventitious weeds
an adventitious insect
3. : adventitial
4. : not congenital : acquired
adventitious deafness
Synonyms: see accidental