Projectors are used for displaying an image on a projection screen or similar surface for the view of an audience.

Video projectors:
LCD projector
CRT projector
DLP projector
LCOS projector

Transparency projectors:
Movie projector
Slide projector
Overhead projector

Other:
Handheld projector (To be used with PDAs and Digital Cameras)
Opaque projector (Reflective projector)
Ceiling projector (Used to measure the base of cloud heights)
Projector (album), by Dark Tranquillity

Mathematics:
Projection operator

Projector was also the name of a version control system developed by Apple Computer as part of the Macintosh Programmer’s Workshop software development system. It has been superseded by CVS.