[dom.i.no] n, pl -noes or -nos [F, prob. fr. L (in the ritual formula benedicamus Domino let us bless the Lord)] (ca. 1694) 1 a (1): a long loose hooded cloak usu. worn with a half mask as a masquerade costume (2): a half mask worn over the eyes with a masquerade costume b: a person wearing a domino
2. a: a flat rectangular block (as of wood or plastic) whose face is divided into two equal parts that are blank or bear usu. from one to six dots arranged as on dice faces b pl but usu sing in constr: any of several games played with a set of usu. 28 dominoes
3: a member of a group (as of nations) expected to behave in accordance with the domino theory