A Zone is a specific kind of Deific Energy, determined by its source.
For example, a person who feels love towards a beautiful women will generate energy flavored both Beauty and Women, and perhaps Lust or another subject. A small amount may be even be flavored with that specific woman. If the woman in question generates a feeling of awe, fear or some other kind of emotion specific to her, she will be the subject of the Zone. Objects, such as a heralded sword, or places, such as a prominent mountain or lake, can also be the subject of Zones. Specific objects, places and people are rarely the source of enough Deific Energy to matter, though there are plenty of counter-examples. In theory, abstract ideas, events or even designs, like a specific song, earthquake or heraldic crest, could constitute a Zone. The more specific the subject, however, the rarer the Zone.
Deific Energy can be used to accomplish various feats. Mortals can use small amounts of it, in the form of Magic, but they can not use more than a very small amount, and many are limited in the Zones they can use. Deities and Pseudodeities can use larger amounts, and are always limited to very specific Zones.
In theory, all magical effects can be created with any Zone, however, it is more efficient to use a Zone that directly relates to that Zone. The more specific the Zone is, the more effective and efficient it will be. Thus, making a specific volcano erupt would be possible for any sufficiently powerful Deity, but it would be more efficient and easier to do a god of fire, and even easier with a god of volcanos or lava, and even easier for a god of that specific volcano.
There is no objective way to to divide Deific Energy into Zones. The line between different Zones is often vague: for example, are Rage and Anger two different Zones? What about Wrath?. We must approximate, which is fine because the rules are not important. The manner in which we Anglish speakers divide feelings into Zones is dependent on Anglish, but it needn't: if a specific society views "a sense of spoiled, victim-based entitlement" as a specific emotion, it could constitute a Zone. Why would you want to make a society that creates such a Zone? This might be a useful plot device; for a familiar example, consider the idea of grokking from Stranger in a Strange Land.
All abstract Zones have a Flaw. For example, if you are a Deity of Secrecy, you can not reveal any secret, under any circumstances. If you are a god of Anger, you must commit all Deific Actions in anger. The page on each specific Zone should explain any relevant Flaws for that Zone - if there is more than one available Flaw, you only have to choose one. Flaws apply to all Avatars and all Deific Actions, even those that are not directly related to the relevant Zone. This means that the more Zones you have, the more limited your actions will be. This is a good reason to sponsor a Demigod.