before vowels chem-, word-forming element denoting "relation to chemical action or chemicals," from combining form of chemical (adj.), used to form scientific compound words from c. 1900. In 19c., chemico- was used.
compound organic chemical, 1959, from DOPA, the amino acid (from first letter of elements of dioxyphenylalanine), + amine.
name of a chemical antagonistic to narcotics, 1964, from elements of N-allynoroxymorphone.