volunteer (n.) Look up volunteer at Dictionary.com
c.1600, "one who offers himself for military service," from M.Fr. voluntaire, noun use of adj. meaning "voluntary," from L. voluntarius "voluntary, of one's free will" (see voluntary). Non-military sense is first recorded 1638. The verb is first recorded 1755, from the noun. Tennessee has been the Volunteer State since the Mexican War, when a call for 2,800 volunteers brought out 30,000 men.