Third Person Limited
Third person limited (TPL) is one of the most common POVs these days. TPL means we the readers are passengers in the POV character’s mind, limited to what he or she notices and thinks. If the character doesn’t see the orc creeping up behind them, the reader doesn’t get to, either.Since the character couldn’t know what the orc is thinking, the reader doesn’t get to, either.
Third Person Omniscient (or, Third Person Unlimited)
In “third person omniscient” (TPO) we would not be limited to the character’s knowledge; the narrator is omniscient, and can get inside anyone’s head. We get to find out what the stalking orc is feeling, what his victim is thinking right before the attack, and even the hidden metal armor the character is wearing under his shirt. TPO was a common POV back in the day, but these days it’s fairly rare.
Third Person Limited also Limits What a Character Would Notice
For instance, if a character has lived on a street all his or her life, she probably won’t even notice any more how it is laid out. So the reader doesn’t get to know either.
Bob paused in the shadow of the alley behind the inn, waiting for the fat man with the fatter purse to exit the bar and stumble by. Across the river the Knarlytooth mountains rose to 8000 feet, glacially carved into spectacular spires of granite and dolomite.
Seriously? Why the hell would Bob pause to think about the geology of the mountains across the water? Answer: he wouldn’t! So the reader doesn’t get to, either.
The only way we get to learn about the mountains is if the mountains were somehow relevant to Bob in that scene–like, say, the moon was about to rise from behind them and reveal his position–then he’s worried about them, and so we get to see them. It might go like this:
Bob paused in the shadow of the alley behind the inn, waiting for the fat man with the fatter purse to exit the bar and stumble by. He glanced over his shoulder at the jagged peaks of the Knarleytooth mountains, the granite spires backlit with the rising moon. Two minutes, maybe less, he judged, before the moon cleared the lowest pass and illuminated the streets. He bit off a curse and returned his attention to the inn. If his mark didn’t show soon, he’d have to give it up.
The rule here is this: filter your world details through the point-of-view character. Make the world details matter to the action/concerns at hand.