"Pending the assent of the parties involved, or a higher authority; subject to agreement by other parties and (now usually) to finalization of the details", Early 18th cent.; earliest use found in Abel Boyer (?1667–1729), lexicographer and journalist. From post-classical Latin ad referendum pending the assent of the parties involved, subject to agreement from classical Latin ad + referendum.[ad referendum etymology, ad referendum origin, 英语词源]