Stories We Like: A Guide to the Comma
1540s, from French extrinsèque, from Late Latin extrinsecus (adj.), from Latin extrinsecus (adv.) "outwardly," from exter "outside" + in, suffix of locality, + secus "beside, alongside," originally "following" (related to sequi "to follow;" see sequel).
extrinsic ex·trin·sic (ĭk-strĭn'sĭk, -zĭk)
Of or relating to an organ or a structure, especially a muscle, originating outside of the part where it is found or upon which it acts; adventitious.