The term 'central part' can be described by a variety of words, each with 6-7 letters. These include 'KERNEL', 'NUB', 'ESSENCE', 'NUCLEUS', 'CORE', 'YOLK', 'HUB', 'PITH', 'HEART', 'MIDST', and 'MIDDLE'. Each of these words refers to the center or innermost part of something, such as the KERNEL of a nut, the NUB of a cigar, the ESSENCE of an idea, the NUCLEUS of an atom, the CORE of an apple, the YOLK of an egg, the HUB of a wheel, the PITH of a plant, the HEART of a matter, the MIDST of a crowd, and the MIDDLE of a range.