volunteer (n.) Look up volunteer at Dictionary.com
c.1600, "one who offers himself for military service," from Middle French voluntaire, noun use of adj. meaning "voluntary," from Latin voluntarius "voluntary, of one's free will" (see voluntary). Non-military sense is first recorded 1630s. 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.