allylic groups

https://doi.org/10.1351/goldbook.A00245
The group CH2=CHCH2 (allyl) and derivatives formed by substitution. The term 'allylic position' or 'allylic site' refers to the saturated carbon atom. A group, such as –OH, attached at an allylic site is sometimes described as 'allylic'.
Source:
PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1315 [Terms] [Paper]