The vinyl group is a common functional group in organic chemistry, consisting of an ethenyl unit attached to a larger molecule. Synonyms for vinyl group include ethenyl, vinylidene, and alk-1-enyl. Another synonym for this group is vinylene, which specifically refers to a double bond between two carbon atoms in a molecule. These terms are often used interchangeably, and all describe the same basic structure. The vinyl group is found in many important compounds including polyvinyl chloride (PVC), which is widely used in construction and consumer goods, and ethylene vinyl acetate (EVA), which is used in adhesives, foams, and packaging materials.