The term METRO GATES is a combination of two words, 'METRO' and 'GATES'. METRO is a type of public transportation system, usually consisting of trains or buses, that operates within a city or metropolitan area. GATES are barriers or entrances that are used to control access to a certain area. In this case, the GATES are used to control access to the METRO system. The term STILES, which has 6 letters, is a type of gate that is used to control access to a public footpath or other area.