chemical 2023.03.13 Meaning of chemical in English Adjective US /ˈkɛməkəl/ UK /ˈkɛmɪkəl/ 1. relating to chemistry or chemicals We must ban chemical weapons. Noun US /ˈkɛməkəl/ UK /ˈkɛmɪkəl/ 1. a substance used in or made by chemistry; chemical substances The factory lets out chemicals in the river.