a Zoom lens is a lens on a camera (still and video both) to get a closer shot of the subject. There are lenses that have both optical zoom and digital zoom capabilities (optical zoom being the better of the two)
"I have a Kodak camera with a 10x optical zoom lens"
by DazzDeLaMorte March 09, 2007
The lazy man's dolly or tracking shot. Used effectively only in cases where speed is needed to grab the audiences' attention.
"We're losing light. Let's use a zoom lens instead of going through the difficulties of pre-planning and executing a superior tracking shot."
by Creedmoor October 11, 2004