What's the story behind Deadpool's name? Most comicbook characters have names that reflect their powers, or even their costumes, but I can't make an association with either his outfit or his healing ability.
In the Deadpool and Death Annual 1999 we learn the origin of Deadpool's name; simply put, when he was being experimented on (as part of the programme which ultimately led to his powers) the guards and inmates had a dead pool where they would gamble on which subject would die next. He took his name from this.
Out of universe, ComicVine indicates that the name (and concept) were chosen as an homage to the 5th Dirty Harry movie. Although they're usually very accurate about these things, I can't find any quotes to back this up.
From an out-of-continuity perspective, co-creator Rob Liefeld had a habit of using action movie titles/ and or pop culture references for character names. Hence, Deadpool, Diehard, Shaft, Bedrock, etc.