[mair-ee klaw-suh
m, mahr-ey; Lat. mah-re klou-soom] 
| a body of navigable water under the sole jurisdiction of a nation. |
| ma·re clau·sum (mä'rā klou'səm, klô'-) n. A navigable body of water, such as a sea, that is under the jurisdiction of one nation and closed to all others. [New Latin : Latin mare, sea + Latin clausum, closed.] |