What Monitor is
The video display unit (or VDU) that sits on your desktop and serves as your computer screen.
The meaning of Cam
An inexpensive, simple video camera that sits on top of or next to your computer monitor, it is designed to send live and recorded video as well as still pictures over the Net to one or more users. It can also be a digital camera placed somewhere, anywhere, in the world, streaming video to a Web site (or other portable device) so that users can see live footage of certain events. The "cam" suffix can be applied to many words to describe specialized cameras, such as "a nannycam," which is used inside a home to monitor a babysitter's activities.