Java
A highly portable, object-oriented programming language developed by Sun Microsystems. Not to be confused with JavaScript (below).
JavaScript
A programming language originally created by Netscape with specific features designed for use with the Internet and HTML, and syntax resembling that of Java and C++. Now standardized as ECMA-262.
JCIC
Joint Committee on Intersociety Coordination.
JEC
Joint Engineering Committee of EIA and NCTA.
jewel box
The plastic clamshell case that holds a CD or DVD.
jitter
Temporal variation in a signal from an ideal reference clock. There are many kinds of jitter, including sample jitter, channel jitter, and interface jitter.
JPEG
Joint Photographic Experts Group. The international committee which created its namesake standard for compressing still images.
JScript
A proprietary Microsoft variant of JavaScript (above).
