1610s, "a medium through which a drug or medicine is administered," also "any means of conveying or transmitting," from French véhicule (16c.), from Latin vehiculum "means of transport, vehicle, carriage, conveyance," from vehere "to bear, carry, convey," from PIE root *wegh- "to go, move, transport in a vehicle," which also is the source of English wagon. Sense of "cart or other conveyance" in English first recorded 1650s.