Ambient Light - any light in the viewing room created by a source other than the projector or screen

Aspect Ratio - the proportion of the screen's width as compared to its height

Aliasing - jagged edges along the outer edge of objects or text

Backlit/Backlighting - the type of lighting used to illuminate LCD displays

Bandwidth - the width, measured in hertz, of a frequency range

BNC - type of connector used for terminating coaxial cable

Build Slide - a slide made up of a series of overlaid slides in which additional objects appear to be added gradually

Color Temperature - a method of measuring the "whiteness" of a light source

Color Resolution - the ability to reproduce fine multicolored picture detail, or the ability to reproduce a sharp transition from one color to another

Contrast Ratio - a metric of a video display defined as the ratio of the light intensity of the brightest possible color a display is capable of to the darkest color a display is capable of

Dot Pitch - a specification for a computer display that describes the distance between phosphor dots (sub-pixels) or LCD cells of the same color on the inside of a display screen

DVI - a video connector designed to maximize the visual quality of digital display devices such as flat panel LCD computer displays and digital projectors

Diagonal Screen Sizing - the distance from one corner of a screen to the opposite corner

Dithering - making digital images appear smoother by adding color or random noise during the digitization process

Digital Light Processing (DLP) - a technology used in projectors and projection televisions in which the image is created by microscopically small mirrors laid out in a matrix on a semiconductor chip

Extended Graphics adapter (XGa) - graphics standard for PCs, with a resolution of 1024 x 768 pixels and generally a refresh rate of 70 Hz or higher

Focal Length - the distance along the optical axis from the lens to the focus

Front Projection - type of TV system in which the picture is projected onto a reflective screen or a wall

Genlock - a technique where the output of one system is used to synchronize another

Ghosting - a problem in LCD screens when tiny pixels creating the image take time to switch on and off and can't do it fast enough

HDTV - the broadcast of television signals with a higher resolution than traditional formats allow

HDMI - provides an interface between any compatible digital audio/video source, such as a set-top box, DVD player, and a/V receiver and a compatible digital audio and/or video monitor, such as a digital television

Hertz (Hz) - the unit of frequency

Horizontal Frequency - represents how many lines are drawn per second

Horizontal Resolution - number of vertical lines (or pixels) that can be resolved from one side of an image to the other

IEEE 1394 (Firewire) - a personal computer and digital video serial bus interface standard offering high-speed communications and isochronous real-time data services

Inverting Images - process by which images from ceiling mounted projectors are corrected so that the projected image is not upside down

Interlacing - a method of displaying images on a raster-scanned display device, such as a cathode ray tube (CRT) that causes less visible flickering than other methods

Keystone Correction - feature found in front projectors designed to compensate for mounting situations when the centerline of the projector's lens is not perpendicular to the screen

Keystoning - distortion that occurs to a projected image resulting in a trapezoid shape rather than a square

Lens Shift - allows flexibility in both the vertical and horizontal positioning of a projector

Liquid Crystal Display (LCD) - a thin, flat display device made up of any number of color or monochrome pixels arrayed in front of a light source or reflector

Long Throw Lens - type of lens that helps create smaller, more viewable images from greater distances

Metal Halide Lamp - type of lamp used in most high-end portable projectors that outputs a very hot temperature light

Multiplexing - the combining of two or more information channels onto a common transmission medium using hardware called a multiplexer

NTSC - the analog television system in use in the United States and some other places

Networking - function that allows two or more computers to exchange information quickly and easily

Overlay - the capability to superimpose computer generated graphics and/or text on motion or still video

Overhead Projector - a display system that is used to display images to an audience. Typically consists of a large box containing a very bright lamp and a fan to cool it, on top of which is a large lens that collimates the light. above the box, typically on a long arm, is a mirror that redirects the light forward instead of up

Phase alteration by Line (PaL) - a color encoding system used in broadcast television systems

Pixel - one of the many tiny dots that make up the representation of a picture in a computer's memory

Projection axis - direction of the imaginary line that extends from the center of the projection lens through the center of the screen

RGB - a color model that utilizes the additive model in which red, green, and blue light are combined in various ways to create other colors

RCa Connector - a type of electrical connector which is commonly used in the audio/video market

Rear Projection - method of projecting images from behind onto a translucent screen

Resolution - the number of pixels that can be displayed on the screen, usually given as a product of the number of columns (horizontal, "X"), which is always stated first and the number or rows (vertical, "Y") to make up the aspect ratio

RS-232C - the standard that describes digital communication between two devices via DB-9 or DB-25 plug connectors

Simulated Color - projected colors that are not the same as the original image

Super VGa (SVGa) - broad term that covers a wide range of computer display standards

Thin Film Transistor (TFT) - special kind of field effect transistor made by depositing thin films for the metallic contacts, semiconductor active layer, and dielectric layer

UXGa - an abbreviation for Ultra eXtended Graphics array referring to a standard monitor resolution of 1600 × 1200 pixels

VGa Resolution - a method used in computer games and to only allow the game to draw to the screen starting at the beginning of a video scan

Varifocal Lens - a projector lens that has three focal elements contained in a single assembly

Vertical Frequency - represents how many frames are formed per second

Vertical Resolution - the number of horizontal lines (or pixels) that can be resolved from the top of an image to the bottom

Vertical Synchronization - a marker in a video signal for the beginning of a frame

Video Graphics array (VGa) - analog graphics card signal (RGB) for PCs with a resolution of 640 x 480 pixels and 60 Hz or 70 Hz refresh rate

Whiteboard - programs that allow multiple users teleconferencing at their own computers to draw and write comments on the same document

Extended Graphics adapter (XGa) - graphics standard for PCs, with a resolution of 1024 x 768 pixels and generally a refresh rate of 70 Hz or higher

Y/C Connector - a 4-pin DIN connector used for high-end S-video sources

Y-Cable - a self describing name of a type of cable containing three ends of which one is a common end that in turn leads to a split into the remaining two ends

Zoom Lens - a mechanical assembly of lenses whose focal length can be changed, as opposed to a prime lens, which has a fixed focal length