(Greek mythology) a sea nymph transformed into a sea monster who lived on one side of a narrow strait; drowned and devoured sailors who tried to escape Charybdis (a whirlpool) on the other side of the strait
A dangerous rock on the Italian coast opposite the whirlpool Charybdis on the coast of Sicily. The passage between Scylla and Charybdis was formerly considered perilous; hence, the saying between Scylla and Charybdis signifies a great peril on either hand.