In my opinion, this is the Protoss equivalent of the Zerg rush. There are really two flavors to the Zealot rush, rushing from your main base or from a proxy.
Here’s a video where the player explains it and how to do it from a proxy.
And here’s a commentary by HuskyStarcraft on Team Liquid invitational a while back on game 1 of WhiteRa vs HayprO where you see WhiteRa pull a proxy Zealot rush for the win.
