"body of water," c.1205, from O.Fr.
lack, from L.
lacus "pond, lake," also "basin, tank," related to
lacuna "hole, pit," from PIE
*lak- (cf. Gk.
lakkos "pit, tank, pond," O.C.S.
loky "pool, puddle, cistern," O.Ir.
loch "lake, pond"). The common notion is "basin." There was a Gmc. form of the word, which yielded cognate O.N.
lögr "sea flood, water," O.E.
lacu "stream,"
lagu "sea flood, water,"
leccan "to moisten" (see
leak). The N.Amer.
Great Lakes so called from 1665.
Laker "boat made for sailing on the Great Lakes" is from 1887.