Dictionary.net

(in Scotland) A tenure where the vassal, in place of military services, makes a return in grain or in money; a sale of land for a stipulated annual payment, esp. for building on.

To let in feu.

In Scot., a conditional allotment of land; property in land held of a superior on payment of a certain annual sum.

To grant a perpetual right to a portion of land on which tenements may be erected, subject to an annual payment called the feu or feuduty.

n. [Scottish] A fief; land held of a superior on payment of an annual rent.