The Collaborative International Dictionary of English v.0.48:

25 \25\ adj.
   1. one more than twenty-four; denoting a quantity consisting
      of twenty-five items or units; -- representing the number
      twenty-five as Arabic numerals

   Syn: twenty-five, xxv
        [WordNet 1.5 +PJC]

WordNet (r) 3.0 (2006):

25
    adj 1: being five more than twenty [syn: twenty-five, 25,
           xxv]
    n 1: the cardinal number that is the sum of twenty-four and one
         [syn: twenty-five, 25, XXV]