The term FISH PART refers to the different parts of a fish. The three solutions for this term are FIN (3 letters), BONE (4 letters), and PECTORALFIN (11 letters). A FIN is a thin appendage used for swimming, which can be found on the back, sides, and tail of a fish. Bones are the hard structures that make up the internal skeleton of a fish. Pectoral fins are the paired fins located on either side of a fish's body, just behind the head.