from
The Collaborative International Dictionary of English v.0.48
adventitious \ad`ven*ti"tious\ ([a^]d`v[e^]n*t[i^]sh"[u^]s), a.
[L. adventitius.]
1. Added extrinsically; not essentially inherent.
Syn: accidental; casual; incidental; additional;
supervenient; foreign.
[1913 Webster + PJC]
To things of great dimensions, if we annex an
adventitious idea of terror, they become without
comparison greater. --Burke.
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2. (Nat. Hist.) Out of the proper or usual place; as,
adventitious buds or roots.
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3. (Bot.) Accidentally or sparingly spontaneous in a country
or district; not fully naturalized; adventive; -- applied
to foreign plants.
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4. (Med.) Acquired, as diseases; not hereditary. --AS
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5. (Med.) Occurring in an unusual place or arising from an
external source. --Stedman 25
[PC] -- {Ad`ven*ti"tious*ly}, adv. --
{Ad`ven*ti"tious*ness}, n.
[1913 Webster]