Biaryl is a term used in organic chemistry to describe a molecule that consists of two aromatic rings attached to each other. There are several synonyms for the word biaryl, including diphenyl, biphenyl, and phenylphenyl. Each of these terms describes the same structural motif of two aromatic rings connected by a carbon-carbon bond. The term biphenyl is the most commonly used synonym for biaryl, and it is often seen in research papers, textbooks, and chemical databases. The use of these synonyms can help to clarify conversations between researchers and simplify the use of specific chemical terms.