Symplegades

[sim-pleg-uh-deez]
plural noun Classical Mythology.
  1. a pair of rocky islands, at the entrance to the Black Sea, that often clashed together: Athena helped the Argonauts navigate them, after which they became fixed.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for symplegades

Historical Examples of symplegades