| a suffix used in the names of radicals: ethyl. |

| -yl suff. An organic acid radical: carbonyl. [French -yle, from Greek hūlē, wood, matter.] |
-yl suff.
A monovalent organic acid radical: carbonyl.
| -yl
A suffix used to form the chemical names of organic compounds when they are radicals (parts of larger compounds), such as ethyl and phenyl. |