any part of an organism such as an organ or extremity

thin structure composed of a single thickness of cells

ridge-like ingrowth of the exoskeleton of an arthropod that supports internal organs and provides attachment points for muscles

a small cup-shaped structure (as a taste bud or optic cup or cavity of a coral containing a polyp)

toothlike structure in invertebrates found in the mouth or alimentary canal or on a shell

the fleshy cushion-like underside of an animal's foot or of a human's finger