nub
[noun]
Synonyms: substance, core, crux, gist, kernel, meat, nubbin, pith, short, upshot

[TahlilGaran] English Synonym Dictionary ▲

nub /nʌb/ noun
[Date: 1500-1600; Origin: Probably from Low German knubbe]

1. the nub of the problem/matter/argument etc the main point of a problem etc:
The real nub of the matter is money.

2. [countable] a small rounded piece of something, especially a piece that is left after the rest has been eaten, used etc

[TahlilGaran] Dictionary of Contemporary English ▲