"something set aside," especially "commodities, agricultural products, etc., reserved by a government for some special purpose, originally military, 1943, from verbal phrase, probably in the sense of "separate out for a particular purpose" (1720); it originally meant "lay aside temporarily" (late 14c.); see set (v.) + aside (adv.). The verbal phrase also is attested as "dismiss from one's mind, leave out of the question" (c. 1400); "put on one side" (early 15c.); "discard or reject from use or service" (1570s).
verbal phrase, mid-13c. (intrans.), "express openly, present to view or consideration, make fully known;" c. 1400 as "leave, begin a journey" (set out in the same sense is from late 14c.); see set (v.) + forth (adv.). The notion of set involved in it is "proceed in a specified direction," hence begin to move" (attested from late Old English). From late 14c. as "prepare and send out, issue" (a commandment, etc.). Of a price from 1520s. Intransitive sense of "go, advance, begin to march" is from mid-14c.