adj acquired, as diseases; accidental.
2. adventitious ·adj out of the proper or usual place; as, adventitious buds or roots.
3. adventitious ·adj added extrinsically; not essentially inherent; accidental or causal; additional; supervenient; foreign.
4. adventitious ·adj accidentally or sparingly spontaneous in a country or district; not fully naturalized; adventive;
applied to foreign plants.