a. [ AS. eahtat&ymacr_;ne, eahtatēne. See Eight, and Ten, and cf. Eighty. ] Eight and ten; as, eighteen pounds. [ 1913 Webster ]
n. 1. The number greater by a unit than seventeen; eighteen units or objects. [ 1913 Webster ]
2. A symbol denoting eighteen units, as 18 or xviii. [ 1913 Webster ]
a. & n. See Octodecimo. [ 1913 Webster ]
a. [ From Eighteen. ] 1. Next in order after the seventeenth. [ 1913 Webster ]
2. Consisting of one of eighteen equal parts or divisions of a thing. [ 1913 Webster ]
n. 1. The quotient of a unit divided by eighteen; one of eighteen equal parts or divisions. [ 1913 Webster ]
2. The eighth after the tenth. [ 1913 Webster ]