The term 'core group' refers to a small group of people who are the most important or influential members of a larger organization. The crossword solutions for this term include 'CADRE, ' which is a small group of people with specialized training; 'seeds, ' which are the beginnings of something; 'middles, ' which are the middle parts of something; 'ABS, ' which stands for anti-lock braking system; and 'SING, ' which means to make a sound with one's voice. Together, these words represent the core group of a larger organization, which is essential for its success.