back forty

or back 40

See synonyms for back forty on Thesaurus.com
noun
  1. remote, usually uncultivated acreage on a large piece of land, as on a farm or ranch.

Origin of back forty

1
Apparently because forty acres was a typical size for such a piece of land

Words Nearby back forty

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023