In 3D imaging, the term "camera" refers to the vantage point from which you're seeing the images.

The theory of 3D imaging is that you specify terrain and objects: their shape, dimensions, and locations. You can then place the camera at any X,Y,Z location and render what the image would look like, assuming you were seeing it from the point where the camera is placed.

For example, a chase camera in a flight sim would fix the camera right behind the plane that the player is flying. Therefore, you would see the landscape below, and the plane foremost in the display. The 3D description the landscape changes as you fly, so that part of the display would change, giving the illusion that your plane is moving through a 3D environment.

On the other hand, a first person camera places the camera right in front of where your subject is. This is the angle usually employed in first-person shooters. In this angle, you see what your character would see, since the camera is viewing images from right where the eyes would be, were it a real life environment.