Wafer
It is a thin slice of semiconductor which is used as a base material to form single transistors or integrated-circuit.

Watt
It is a unit of electrical power which measures the rate of energy produced or consumed by any electrical device. 1 watt = 1 joule of energy per second. The name comes from a Scottish engineer of 18th century, James Watt.

Wavelength
It is the physical distance between the beginning and the end of identical points in adjacent waves of electromagnetic signals propagated in space or through a conductor. Wavelength is measured in meters, centimeters, or millimeters or in Angstrom units and is designated with the Greek letter lambda (l). It is inversely related to frequency i.e. higher frequency means shorter wavelength.

XGA or XGA-2
Stands for eXtended Graphics Array Card. It is an IBM's graphics standard that have VGA and an extended resolutions up to 1024 x 768 (interlaced 35 kHz) with 65k colors. XGA-2 is the 2nd generation card which is also capable of scanning form 31 to 68 kHz. It has a resolutions up to 1600 x 1200 pixels. Both the card uses a 15-pin HD VGA-style connector.

XLR Connector
Also known as cannon connector. It is a secure connector found on high quality audio and video equipment with three leads, two of them are for signal and the remaining one for overall system grounding.