appendage

Appendix isn't the only noun that comes from append. Unlike appendix, appendage doesn't suggest the end of something, but simply something attached. The word is often used in biology to refer to parts of an animal's body: an insect's antennae, mouthparts, or wings, for example. The appendages of some animals will grow back after they've been removed; a salamander, for example, can regrow a finger, and the tiny sea squirt can regrow all its appendages—and even its brain.