the.com/back forty

The farthest acres from the house, where fences loosen and rules get negotiable.

means A remote, out-of-the-way piece of land (or by extension, any far-off, low-scrutiny corner of life) distant enough from the main house that nobody's watching too closely.

from Comes straight from American land surveying: under the old quarter-section system, a 160-acre farm was commonly divided into quarters of forty acres each, and the 'back forty' was the parcel farthest from the farmhouse and road — the rough, untended ground out past the fields you actually tended. It entered everyday speech as a jokey stand-in for 'way out there, off the beaten path,' with no single coiner — just generations of farm talk drifting into general use.

origin
from 40-acre land survey plots, US homesteading
usage
often not literally forty acres
connotation
implies remote, unsupervised, slightly lawless territory
modern use
metaphor for any neglected far corner
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