The Action model has advanced a lot, it now includes multi targetting, Action recursion, world infinite timeline, amongst other things. The basics are that if the player wants to do something, and his PC can do it, then the UI (or the AI) must let him do it. The Action begins with the intention of the Being, then it is performed and then its cost calculated. All Spells are Actions, all skills are actions, everything that includes a Being interacting with anything else is an Action.

Advance, Open, Close, Fire Beam, Ice Beam, EarthQuake, Identify Item, are all different kinds of actions, but in the end they all share the basic idea, a Being exploiting one of his capabilities to influence the world he exists in.