Merriam-Webster Collegiate Dictionary - six

 noun  Etymology: Middle English, from ~, adjective, from Old English siex; akin to Old High German sehs ~, Latin sex, Greek hex  Date: before 12th century  1. — see number table  2. the ~th in a set or series the ~ of spades  3. something having ~ units or members: as  a. an ice-hockey team  b. a 6-cylinder engine or automobile  • ~ adjective  • ~ pronoun, plural in construction