word-forming element meaning "physical, physically; natural," from Latinized form of Greek physikos "natural, physical, pertaining to nature" (from PIE root *bheue- "to be, exist, grow"). Compare physic.
1570s, "relating to chemistry, pertaining to the phenomena with which chemistry deals," from chemic "of alchemy" (a worn-down derivative of Medieval Latin alchimicus; see alchemy) + -al (1). In early use also of alchemy. Related: Chemically. Chemical warfare is attested from 1917.