mole 3 
(mōl)
(mōl)n.
1. A massive, usually stone wall constructed in the sea, used as a breakwater and built to enclose or protect an anchorage or a harbor.
2. The anchorage or harbor enclosed by a mole.
[French môle, from Italian molo, from Late Greek mōlos, from Latin mōlēs, mass, mole.]