To smoke marijuana in any fashion with any type of smoking device.
"Hey man, want to burn?"
"Man, we burned a blunt last night and I was so high!"
"Bro, I was at the beach burning and surfing all day"
Coding an application or developing a web page
Did you see that website. That's a cool burn.
In use in South Africa in the 60s and 70s - means to drive at excessive speed. When two or more vehicles are involved, a 'burn' became a 'dice'
"Hey, Jack, those are nice wheels. let's go for a burn."