A pit is a hole in the ground, like the one in Poe’s “The Pit and the Pendulum” that the narrator tries not to fall into. A pit can also be smaller indentation. There’s also a pit hiding inside a peach.
Pit is a word with a wide variety of meanings. There's the pit you dig on the beach as a moat for your sandcastle, and the pit a hunter digs for trapping an animal. Then there's the sunken area of a performance hall where musicians play, an orchestra pit, and the area that's reserved for certain activity, like the trading pit at a stock exchange. Finally, a pit is also a large, hard seed — like a peach pit.