DC stands for "depressed characters". Two fine examples:

Batman suffered from PTSD as a child so to cope with it he dresses up as a bat and runs around at night throwing boomerangs at people.

Spiderman broke into a lab, got bit by a radioactive spider so he dressed up in elastic and swings around on the buildings.

There are very likely more examples, but those two are the ones I know so far.

These pieces of information came from my younger sister who is a Marvel fan. She's not too fond of DC for some reason.