Definition of Waif
A castaway; a homeless child. | (botany, of a plant outside its native range) A plant that has been introduced but is not persistently naturalized. | (obsolete) Goods found of which the owner is not known; originally, such goods as a pursued thief threw away to prevent being apprehended, which belonged to the king unless the owner made pursuit of the felon, took him, and brought him to justice.