What makes a game casual?

being able to pick it up and play, AND be good at it from the start. PSBox3SixWi

That makes almost all games casual for some players then...

I can pick up almost any FPS, Racing game etc and be good at it straight away because I've played so many I'm just good at them, know how they control. Sure racing games have different handling but I get over that in a few minutes.

I'd say it's more about who players it, so if it's played by a majority of casuals then yeah it is.