'antimicrobial' originates from the combining prefix 'anti-' (from Greek anti- meaning 'against') plus 'microbial', which derives from 'microbe' (from French 'microbe', ultimately from Greek 'mikros' meaning 'small' and 'bios' meaning 'life').

'antimicrobial' was formed in English by combining the prefix 'anti-' with the adjective 'microbial' (itself from 'microbe', a 19th-century coinage from French and Greek roots). Over the late 19th and early 20th centuries 'microbe' and 'microbial' entered scientific usage, and 'antimicrobial' was created to describe agents acting against microbes.

Initially it meant 'against or opposing microbes'; over time the term's use broadened to refer specifically to medicines, chemicals, or materials that kill or inhibit bacteria, fungi, viruses, or protozoa (not only a generic 'against microbes').