Unimolecular is a term used to describe reactions or processes that involve one molecule. Synonyms for unimolecular include monomolecular, singular, individual, and solitary. These words can be used interchangeably to describe reactions that occur within a single molecule. For example, a unimolecular reaction may involve the breakdown of a single molecule into smaller fragments without the involvement of any other molecules. Synonyms such as singular and individual emphasize the solitary nature of the molecule, while monomolecular specifically refers to the involvement of a single molecule. Overall, these synonyms are useful for describing reactions that only involve a single entity.