Propyl radical is a term that refers to the chemical structure of a molecule containing three carbon atoms with one unpaired electron. There are several synonyms for propyl radical, including prop-1-yl, 1-propyl, and propylidyne. Propyl is often used interchangeably with n-propyl, which denotes a linear alkyl group, whereas iso-propyl refers to a branched alkyl group. Additionally, propyl radical can be described as a primary alkyl radical, as opposed to a secondary or tertiary alkyl radical. The main sources of propyl radicals are from reactions involving hydrocarbons and halogens or oxygen-containing species. These synonyms provide a variety of ways to describe this important chemical structure in organic chemistry.