'Thirlage' definitions:
- Thirlage \Thirl"age\, n. [Cf. Thrall.] (Scots Law)
The right which the owner of a mill possesses, by contract or
law, to compel the tenants of a certain district, or of his
sucken, to bring all their grain to his mill for grinding.
--Erskine.
[1913 Webster]