JFCL (djif'kl or dja-fik'l)
[based on the PDP-10 instruction that acts as a fast no-op]
v. To cancel or annul something. "Why don't you jfcl that out?" [The licence plate on Geoff Goodfellow's BMW is JFCL.]

JIFFY
n. 1. Interval of CPU time, commonly 1/60 second or 1 millisecond.
2. Indeterminate time from a few seconds to forever. "I'll do it in a jiffy" means certainly not now and possibly never.

JOCK
n. Programmer who is characterized by large and somewhat brute force programs. The term is particularly well-suited for systems programmers.

J. RANDOM
See RANDOM.

JRST (jerst)
[based on the PDP-10 jump instruction]
v. To suddenly change subjects. Usage: rather rare. "Jack be nimble, Jack be quick; Jack jrst over the candle stick."

JSYS (jay'sis), pl. JSI (jay'sigh)
[Jump to SYStem]
See UUO