Meaning

originFrom dialectal nug, nog, knog (“a knot, lump, block, a misshapen mass of anything, peg, linchpin”), also found in Scots nug, nugg, nogg (“small block of wood, peg, pin”), of uncertain origin. Probably from earlier *knug, *knugg, *knogg, related to dialectal Norwegian knugg (“knot, knob”), ultimately from Proto-Germanic *knuk- (“to ball up, mass together”), making it further related to English…

Etymology from Wiktionary, CC BY-SA 3.0