I have stumbled quite a few times about the expression "nova" in combination with the monk. What does it mean? E.g. "for building up nova rounds".
The term Nova in 4e is not specific to the monk, it's not specific to any particular class, though it's something that a lot of striker builds center around.
Typically what it means is that you'll spend all of your actions in a given round (and many of your resources) on a single set of attacks. A typical nova involves the spending of an action point, and if available, one or two minor action attacks.
Many novas require a round to set up (such as getting into a stance or activating an aura or possibly both) and expend much of your encounter level resources and some daily level resources.
Here is an example of a Nova from a daggermaster rogue with two-weapon fighting and an OK MBA:
With a turn to set up, the Rogue is dealing mongo damage to a single (or a couple) of targets with the tradeoff of using a lot of resources. This is the kind of round series that will change an encounter and can be game breaking.
With regards to a monk specifically, their options for pulling off a nova are more limited than other strikers. They do not have any minor action encounter attacks, though you can take a theme that will add one, this limits the amount of damage you can do in a single round (at most 3 attacks in a single round). They do have a feat to let you use Flurry of Blows again following an action point.
All that to say, if you want to go Nova, the monk is not a good choice. This thread has a L16 monk that does OK, but it's not a top nova build at 16 by any stretch (The Rogue I outlined properly equipped would outclass that fairly easily).
Nova means spending a lot of resources for a spectacular result.
In DnD4, you use several encounter and possibly daily powers, item powers, and possibly even an action point, to achieve as much damage as possible. It is a Nova, because:
Novas are not specific to Monks, and in my understanding it is not a special build, it is a special sequence of actions of any build. Of course you can optimize a build for Nova or for At-will, but all classes have options to do more damage for a limited time.
The round a 1st level Knight uses his only Power Strike can be considered his Nova round.