Friends you never talk to albeit saying "Hello" and "Goodbye" while passing in the halls. These friends are usually people that you have classes with, people you've done a group project with, lab partners, etc.
"Sara is your friend right?"
"Nah, we did a project together last year; she's a HelloGoodbye Friend."
Nickname given to bales of marijuana thrown overboard or out of airplanes. Origin is reportedly from members of the US Coast Guard in the area of Southern Florida.
A sunburn or suntan focused on the left arm. It is caused by the left side of the body being the only half that gets exposed to sunlight while driving. Presumably, it would be located on the right side of the body in countries where they drive on the left side of the road.
I had a trucker's tan after driving for 10 straight hours on a sunny day.