nub nəb/ noun noun: nub; noun: the nub; plural noun: nubs 1.the crux or central point of a matter. "the nub of the problem lies elsewhere" synonyms: crux, central point, main point, core, heart, heart of the matter, nucleus, essence, quintessence, kernel, marrow, meat, pith; More 2. a small lump or protuberance. "he pressed down on the two nubs on top of the phone" 3. a small chunk or nugget of metal or rock. "a nub of gold" Hmm...not the exact definition of nub that I had in mind, but it'll do.