Definify.com

Webster 1913 Edition

Noun.

A stone composed of sand or grit; – so called because it is easily cut or wrought.

Adj.

Having the flesh readily separating from the stone, as in certain kinds of peaches.

Noun.

Any species of stone composed of sand or grit, so called because it is easily cut or wrought.

See also: free-stone

freestone ‎(plural freestones)

A type of stone that is composed of small particles and easily shaped, such as sandstone or limestone.
- 1749, Henry Fielding, The History of Tom Jones, a Foundling
  Mr Allworthy […] died immensely rich and built an hospital […] but had he done nothing more I should have left him to have recorded his own merit on some fair freestone over the door of that hospital.
A stone fruit having a stone (pit) that is relatively free of the flesh.