One of the mysteries of the English language finally explained.
A day on which feudal tenants, on demand, performed harvest work for the lord of the manor.
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.
magna precaria/ˈmaɡnə prɪˈkɑːrɪə//ˈmaɡnə prɪˈkɛːrɪə/
In this article we explore how to impress employers with a spot-on CV.