gulf -
an arm of a sea or ocean partly enclosed by land; larger than a bay
body of water,
water the part of the earth's surface covered with water (such as a river or lake or ocean); "they invaded our territorial waters"; "they were sitting by the water's edge"
sea a division of an ocean or a large body of salt water partially enclosed by land
gulf -
an unbridgeable disparity (as from a failure of understanding); "he felt a gulf between himself and his former friends"; "there is a vast disconnect between public opinion and federal policy"