A dome camera gets it name from the shape of the housing it sits in, it is usually fixed to the ceiling of the property to be secured and gives a 360 degree view of the area under the roof. Dome shaped cameras usually come with a pan/tilt/zoom option and operators will have the ability to move the camera.
It is a useful option when you want to cover a large area with one camera. Due to it’s dome shape it gets difficult to tell as to where is the camera pointing, hence deterring possible threat.