Noun

• S: (n) nub, nubble (a small lump or protuberance)
• S: (n) nub, stub (a small piece) "a nub of coal"; "a stub of a pencil"
• S: (n) kernel, substance, core, center, centre, essence, gist, heart, heart and soul, inwardness, marrow, meat, nub, pith, sum, nitty-gritty (the choicest or most essential or most vital part of some idea or experience) "the gist of the prosecutor's argument"; "the heart and soul of the Republican Party"; "the nub of the story"