Acis in Greek mythology, was
(1) the son of Faunus and of Symaethis. Galathea, the fairest of the nymphs, was his beloved. She was also loved by the giant Polyphemus, and he followed her wherever she went. One day Polyphemus espied the pair sitting in the shade of a large tree. Full of anger and jealousy, he threw a large stone upon the two lovers. The beautiful young goddess made a hair- breadth escape; but Acis was crushed by the huge rock. He was afterwards converted into a river springing out from under this rock.
(2.) A river-god, the tutelary deity of the town of Acium, in Sicily.