late 14c. (harmofroditus), from Latin hermaphroditus, from Greek hermaphroditos "person partaking of the attributes of both sexes," as a proper name, the son of Hermes and Aphrodite, who, in Ovid, was loved by the nymph Salmacis so ardently that she prayed for complete union with him and as a result they were united bodily, combining male and female characteristics.
Also used figuratively in Middle English of "one who improperly occupies two offices." As a name for the condition, Middle English had hermofrodito (late 14c.), hermofrodisia (early 15c.). As an adjective, from c. 1600. Also used of things of two natures, such as hermaphrodite brig, for a vessel square-masted fore and schooner-rigged aft.