Especially in Ireland: a grant, made by the Exchequer, of the custody of land or other property belonging to the British Crown to a person for a certain period of time, giving the lessee the right to collect rents from the land or property granted. In later use sometimes more fully "custodiam lease", "custodiam grant".
Custodiam grants were commonly used by the Exchequer to enforce the payment of debts by taking lands owned by an insolvent debtor into the possession of the Crown, and granting custody of them to the creditor until the debt had been paid out of the rents earned.
Early 17th century; earliest use found in Fynes Moryson (?1566–1630), traveller and writer. From classical Latin custōdiam, accusative of custōdia custody, in the wording of the grant; compare post-classical Latin Sciatis quod commisimus…custodiam omnium terrarum et tenementorum ‘Know ye that we have granted…the custody of all lands and tenements.’ (or similar), in the text of a grant issued by the Chancery.