There's the so-called Berlin Interpretation[0] which attempts to codify exactly what a roguelike is, basically, according to that definition, if it isn't a turn based gridlike hack and slash in randomly generated dungeons with permadeath, it isn't a roguelike. Of course, /r/roguelikedev will point out that the most popular roguelikes all deviate from that in one way or another, and people do seem to disagree[1] with the definition.

I personally don't think the distinction matters that much, except to pedants and purists.

[0]http://www.roguebasin.com/index.php?title=Berlin_Interpretat...

[1]http://www.gamesofgrey.com/blog/?p=403