"not of the essence or inner nature of a thing," 1540s, from French extrinsèque, from Late Latin extrinsecus (adj.) "outer," from Latin extrinsecus (adv.) "outwardly, on the outside; from without, from abroad," from exter "outside" + in, suffix of locality, + secus "beside, alongside," originally "following," from PIE *sekw-os "following," from root *sekw- (1) "to follow" (see sequel).