- propaneAn aliphatic hydrocarbon, C₃H₈, a constituent of natural gas.
- propyleneThe organic chemical compound propene. An alkene which is a colorless gaseous (at room temperature and pressure) hydrocarbon with the chemical formula C₃H₆.
- propionicOf or pertaining to propionic acid or its derivatives; propanoic
- prop-Denoting the presence of 3 carbon atoms in the parent chain when forming names of organic compounds.