'mare liberum' definitions:

Definition of 'mare liberum'

From: WordNet
noun
(free sea) a navigable body of water to which all nations have equal access

Definition of 'mare liberum'

From: GCIDE
  • mare liberum \mare liberum\ n. [L., free sea.] A navigable body of water to which all nations have equal access; the opposite of mare clausum. [WordNet 1.5]