Sclerite

A sclerite (Greek σκληρός, sklēros, meaning "hard") is a hardened body part. In various branches of biology the term is applied to various structures, but not as a rule to vertebrate anatomical features such as bones and teeth. Instead it refers most commonly to the hardened parts of arthropod exoskeletons and the internal spicules of invertebrates such as certain Porifera and soft corals. Used as a universal term of convenience, the word is vague and takes different meanings according to various needs. For example, the trend not to refer to say, vertebrate teeth as sclerites, is arbitrary, and the so-called sclerites of sponges have very little to do with the sclerites of arthropods.