Precariae
Defined in 2 dictionaries — Cyclopedic (1922), Ballentine's (1916)
The Cyclopedic Law Dictionary
Walter A. Shumaker and George Foster Longsdorf; ed. James C. Cahill · 1922
or PRECES (Law Lat.)
In old English law. Days' works, which the tenants of some manors were bound, by which Spelman supposes to be a corruption of "biden days," which in Saxon, answered to dies precariae (literally, pray days, or praiyed days), the Saxon biden signifying to pray. Spelman; Cowell.
Ballentine's Law Dictionary
James A. Ballentine · 1916
Day’s work performed as an incident to certain tenures.