Source : Webster's Revised Unabridged Dictionary (1913)

Acreage \A"cre*age\, n.
   Acres collectively; as, the acreage of a farm or a country.

Source : WordNet®

acreage
     n : an area of ground used for some particular purpose (such as
         building or farming); "he wanted some acreage to build
         on" [syn: {land area}]