Added extrinsically; not springing from the essence of the subject, but from another source; foreign; accidentally or casually acquired: applied to that which does not properly belong to a subject, but which is superadded or adopted, as in a picture or other work of art, to give it additional power or effect.In botany and zoology, appearing casually, or in an abnormal or unusual position or place; occurring as a straggler or away from its natural position or habitation; adventive.In anatomy, of the nature of adventitia: as, the adventitious coat of an artery.In phytogeography, naturalized from a distant formation: opposed to *vicine. A term proposed by Pound and Clements. Compare adventitious, 2.