Gulf of Mexico - an arm of the Atlantic south of the United States and east of MexicoAtlantic, Atlantic Ocean - the 2nd largest ocean; separates North and South America on the west from Europe and Africa on the east Bay of Campeche - a bay of the Gulf of Mexico; formed by the Yucatan Peninsula Galveston Bay - an arm of the Gulf of Mexico in Texas south of Houston gulf - an arm of a sea or ocean partly enclosed by land; larger than a bay Mobile Bay - a bay of the Gulf of Mexico; fed by the Mobile River Tampa Bay - an arm of the Gulf of Mexico in west central Florida |