Unprecedented means never having happened before in all history. An unprecedented step, unprecedented demand, truly unprecedented.
It is a strong claim and it is made far too easily — unprecedented in living memory and unprecedented since records began are the honest versions, and records rarely go back very far. In law it means no earlier case governs, which is a precise and consequential thing to say. Note precedent; and that unprecedented is that word negated.
1adjectiveunprecedentedNever having happened before in all history.
“The storm brought unprecedented flooding to the old town centre.”
unprecedented is a quality of being first.
Latin
praecēdēns
English
precedent
English, today
unprecedented
Built from
From un- + precedent + -ed. precedent comes from Middle French -, from Old French -, from Latin praecēdēns, present participle of praecedo (“to precede”); See precede.
Etymology from Wiktionary, CC BY-SA