Somewhat common Videogame Slang. Means "To Own", which connotates victory on some level.

A person with an outwardly dominant, masculine, or aggressive personality, but who also enthusiastically takes on the submissive or "bottom" role in the bedroom.

Noun - Someone/thing that owns.

one that "owns"

The act of "owning", or being better at something than someone.

aka 0wnz0r (with zeros replacing the o's)