X

XCOFF

See: Extended Common Object File Format (XCOFF)

XO

See: exactly-once (XO) transaction

XOR mode

A transfer mode type in which the bits of the source color component and destination color component are combined using an exclusive-OR operation.

XPT

See: transport (XPT)

XYZ color space

The fundamental CIE-based color space that allows colors to be expressed as a mixture of the three tristimulus values X, Y, and Z.

x-height

The height of a lowercase x in a given font. It is the height, measured from the baseline, of the main portion of most lowercase letters (excluding ascenders and descenders)

See also: ascent line, baseline, descent line