Origin: 1250–1300; Middle English expounen,expounden < Old French espondre < Latin expōnere to put out, set forth, explain, equivalent to ex-ex-1 + pōnere to put
c.1300, from O.Fr. expondre, from L. exponere "put forth, explain," from ex- "forth" + ponere "to put, place" (see position); with intrusive -d. Related: Expounded; expounding.