Webster's Revised Unabridged Dictionary · 1913

Eighty

Eighty , adjective

[Anglo-Saxon eahtatig, where the ending -tig is akin to English ten; compare German achtzig. See Eight, and Ten.]

Eight times ten; fourscore.

Eighty , noun

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.