What Does 'Action Combat' Mean?

I have no idea, how about you? So here's the deal. Next time I find myself in an argument about 'rooted' ability animations, or 'Action Combat' or what makes TERA different from WoW, or how you can make an action bar full of situational buttons without needing extra keys for a damage rotation, i'm going to save myself several pages worth of text and just link this video. I expect over the coming decade this video shall save me upwards of 200 hours worth of pointless Internet arguments. With my extra 200 hours worth of free time, I shall endeavour to shave more frequently.