Stone which lies at the corner of two walls and unites them; implies a sense of foundation in that the building would fall to ground without the cornerstone.
"This law is implicit in earlier work, but Lavoisier stated it explicitly and used it as the cornerstone of his science."
"Yoga and meditation were the cornerstone to the success of the state ranker."
To do something with less than the appropriate amount of care. Possibly from the practice of taking a short cut when running around a city block, effectively cuting off a corner of the route.
If they hadn't cut so manycorners when building that bridge, it probably wouldn't have fallen down.
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.