Hylas was the son of Theodamas, king of the Dryopes, and the nymph Menodice. Heracles fought his father, abducted Hylas, and became his lover. His name derives, it seems, from hyle, 'wood', so that he is in some way connected with a wood (living in one or born in one, perhaps, although we are not given any specific connection).

The poet Theocritus tells how Hylas had a festival annually at which his devotees would roam the mountains calling out his name. Perhaps this mourning or lamenting actually gave rise to his name, in other words it derives from the verb hylao, 'to howl' (which is related to the howling known attractively in English as 'ululation').