look up any word, like dirty sanchez:
 
1.
refers to the left arm being tanner (or redder) than the right arm because it's been hanging out the window
dude1: hey man i took a trip to LA last weekend...
dude2: yea man i know... you've got major driver's arm!
by Chrissy12321 June 04, 2006
 
2.
n. Refers to the left arm's being burned or more tan than the right, as long as the driver is from the majority of countries where people drive on the right side of the road.
His farmer's tan gradually became driver's arm after he quit farming and started truck driving.
by luvswerds July 04, 2009
 
3.
refers to the RIGHT arm being tanner (or redder) than the left arm because it's been hanging out of a car window during transit.

"What's wrong with your arm? You get sunburnt?"
"Yea, driver's arm from the trip to Queensland, got bloody bitten by mossies too!"
by Count23 May 08, 2007