nick = N = night mode

nickle /ni'kl/ n.

[from `nickel', common name for the U.S. 5-cent coin] A nybble + 1; 5 bits. Reported among developers for Mattel's GI 1600 (the Intellivision games processor), a chip with 16-bit-wide RAM but 10-bit-wide ROM. See also deckle, and nybble for names of other bit units.

--The Jargon File version 4.3.1, ed. ESR, autonoded by rescdsk.