magna precaria
/ˈmaɡnə prɪˈkɑːrɪə/ /ˈmaɡnə prɪˈkɛːrɪə/Feudal Law. historical
noun
A day on which feudal tenants, on demand, performed harvest work for the lord of the manor.
Origin
Early 18th century; earliest use found in Phillips's New World of Words. From post-classical Latin magna precaria a reaping day from magna, feminine singular of magnus great + precaria.