Proteid

noun

1. A protein. No longer in scientific use.
2. In zoöl, an amphibian of the family Proteidæ.
3. A substance formerly supposed to contain protein as an essential ingredient.
4. an older, imprecise term replaced by protein.
5. one of a class of proteid substances, present in some animal tissues and fluids, that make the body immune to certain infectious diseases by destroying or rendering inactive the toxic products of bacterial growth; -- this is an older term replaced by more precise modern immunological concepts such as antibody and immunoglobulin.