Definition: 1. Xanthyl is a chemical reaction that takes place during the dehydrogenation of cyclopentadiene into cyclopentenone in organic chemistry. 2. The term 'xanthyl' describes the intermediate product formed in this process.<0x0A><0x0A>Definition:<0x09>Xanthyl - A chemical reaction that occurs during the dehydrogenation of cyclopentadiene into cyclopentenone in organic chemistry. Intermediate product.