Source : Webster's Revised Unabridged Dictionary (1913)

Eighty \Eight"y\, a. [AS. eahtatig, where the ending -tig is
   akin to English ten; cf. G. achtzig. See {Eight}, and {Ten}.]
   Eight times ten; fourscore.

Eighty \Eight"y\, n.
   1. The sum of eight times ten; eighty units or objects.

   2. A symbol representing eighty units, or ten eight times
      repeated, as 80 or lxxx.

Source : WordNet®

eighty
     n : the cardinal number that is the product of ten and eight
         [syn: {80}, {LXXX}, {fourscore}]

eighty
     adj : being ten more than seventy [syn: {80}, {lxxx}, {fourscore}]