Handler and Driver

handler

One who trains or exhibits animals.
- synonyms: animal trainer
An agent who handles something or someone.
- usage: "the senator's campaign handlers"
Sports) someone in charge of training an athlete or a team. (.
- synonyms: coach, manager

driver

The operator of a motor vehicle.
Someone who drives animals that pull a vehicle.
A golfer who hits the golf ball with a driver.
Computer science. ( a program that determines how a computer will communicate with a peripheral device)
- synonyms: device driver
A golf club (a wood) with a near vertical face that is used for hitting long shots from the tee.
- synonyms: number one wood

(n.) An overseer of a gang of slaves or gang of convicts at their work.
(n.) An attachment to a lathe, spindle or face plate to turn a carrier.
(n.) The person who drives beasts or a carriage; a coachman; a charioteer, etc.; hence, also, one who controls the movements of a locomotive.
(n.) A part that transmits motion to another part by contact with it or through an intermediate relatively movable part, as a gear which drives another or a lever which moves another through a link, etc. Specifically:.
(n.) The after sail in a ship or bark, being a fore-and-aft sail attached to a gaff; a spanker.
(n.) One who or that which, drives; the person or thing that urges or compels anything else to move onward.
(n.) The driving wheel of a locomotive.
(n.) A crossbar on a grinding mill spindle to drive the upper stone.

Webster's Revised Unabridged Dictionary