Fruit stone is a term used to describe the hard outer layer of certain fruits, such as peaches, plums, and cherries. The crossword solutions for this term are PIT (3 letters), SEED (4 letters), and NUTLET (6 letters). A PIT is the hard, inner core of a fruit, while a SEED is the small, hard part inside the fruit that can be planted to grow a new plant. A nutlet is a small, hard nut-like structure found in some fruits.