1946, Bertrand Russell, History of Western Philosophy, I.30:His life is almost co-extensive with one of the most disastrous periods in Roman history.
(logic) Having the same extension—the object or set of objects to which a term refers.
1995, Jaegwon Kim, Ernest Sosa, A Companion to Metaphysics, Coextensive expressions with different intensions cannot in general be substituted for one another within an expression e while preserving the extension of e (assuming that the extension of a declarative sentence is its truth value).
