area of expertise, a particular skill;

In baseball this is the part of an individual's swinging range in which as a hitter they can make the best contact with the ball. If a pitch is right in your wheelhouse it is right where you want it, in the spot where you have the best chance of hitting it well.

The term is also often used to explain something that falls into a person's area of expertise.

Anything that can be acted on with confident success.
I'm guessing it originates from the fact that a wheelhouse is the room on the bridge of a ship where you steer from, providing you with clear view & control to steer the situation.

someone's personal space. can be used when someone is in your face, or in your business.

Comedy Motor Home Option

Location or area on the front of the human body between the neck and the abdomen.