(Attack Action: An attack action is a type of standard action. Some combat options can modify only this specific sort of action. When taking an attack action, you can apply all appropriate options that modify an attack action. Thus, you can apply both Greater Weapon of the Chosen and Vital Strike to the same attack, as both modify your attack action. You can apply these to any combat option that takes the place of a melee attack made using an attack action (such as the trip combat maneuver), though options that increase damage don’t cause attacks to deal damage if they wouldn’t otherwise do so (such as Vital Strike and trip). You can’t combine options that modify attack actions with standard actions that aren’t attack actions, such as Cleave. Source: PZO9468)
So I find this confusing is a attack action just a fancy way of saying that its a standard action?
Yes the attack action is when you use a Standard action to make a single attack. It's not anytime you would make an attack or any action that is an attack.
The attack action is a specific type of standard action used to make an attack. Some things like the vital strike feat are able to be used alongside an attack action specifically.
Other things like the standard action used by the cleave feat are a different type of standard action and do not use the attack action, meaning things like vital strike cannot normally be used alongside it.
The "attack" action is one specific kind of standard action, just like the "activate magic item" action, the "total defense" action, and so on. An "attack" may be made as part of an attack action, part of a full-attack action, an attack of opportunity, or some less common cases. Things that say they work "as part of an attack action" (e.g., Vital Strike) only work with the "attack" action, not a full-attack or some other kind of attack. Things that define their own action (e.g., Cleave, Spring Attack) don't work with any other actions . . . unless a more specific rule says otherwise, of course.