18 possible answers to
Answers with 3 characters: COR NUB Answers with 4 characters: CORE CRUX GIST MEAT PITH Answers with 5 characters: MIDST Answers with 6 characters: CENTER KERNEL METTLE MIDDLE TICKER Answers with 7 characters: COURAGE ESSENCE Answers with 15 characters: CENTERORESSENCE DAMNYANKEESTUNE VALENTINESYMBOL