The Collaborative International Dictionary of English v.0.48:

80 \80\ adj.
   1. one more than seventy-nine and one less than eighty-one;
      denoting a quantity consisting of eighty items or units;
      -- representing the number eighty as Arabic numerals

   Syn: eighty, lxxx, fourscore
        [WordNet 1.5 +PJC]

WordNet (r) 3.0 (2006):

80
    adj 1: being ten more than seventy [syn: eighty, 80, lxxx,
           fourscore]
    n 1: the cardinal number that is the product of ten and eight
         [syn: eighty, 80, LXXX, fourscore]