'Unearned increment' definitions:

Definition of 'unearned increment'

(from WordNet)
noun
An unearned rise in the market value of property resulting from general market factors

Definition of 'Unearned increment'

From: GCIDE
  • Unearned \Un*earned"\, a. Not earned; not gained by labor or service. [1913 Webster]
  • Unearned increment (Polit. Econ.), a increase in the value of land due to no labor or expenditure on the part of the owner, but to natural causes, such as the increase of population, the growth of a town in the vicinity, or the like. Some hold that this should belong to the nation. [1913 Webster]