A camera records images in the form of photographs, film or video. If you want evidence that you've spotted Bigfoot in the woods behind your house, you'll need a camera.
The noun camera typically refers to a film or digital device that captures still pictures when you press a button. A film camera stores images on a strip of film that must be developed with special chemicals, while a digital camera keeps them on a memory card, and with the help of a computer you can see the pictures almost instantly. The original meaning of camera, "vaulted building," came from Latin via the Greek root kamera, "vaulted chamber."