The term 'small knot' can be described by two crossword solutions: NODULE (6 letters) and BURL (4 letters). A NODULE is a small, rounded lump or mass of tissue, often found in the body. It can also refer to a small, round mineral deposit. A BURL is a type of growth on a tree trunk or branch that is caused by a fungus or virus. It is characterized by a lumpy, knotted surface and is often used to make furniture and other decorative items.