The C-terminus is the end or tail of a protein or peptide chain, and there are several synonyms commonly used to describe this region. Some of these synonyms include the carboxy terminal, C-terminal end, COOH-terminal, and carboxyl end. The C-terminus is important in protein function as it contains domains for protein-protein interactions, signaling, and enzymatic activity. It also plays a crucial role in protein folding and stability, and mutations in this region can lead to disease. Understanding the various synonyms for the C-terminus is important for effective communication in the scientific community.