"destructive to micro-organisms," 1894, from French antibiotique (c. 1889), from anti- "against" (see anti-) + biotique "of (microbial) life," from Late Latin bioticus "of life" (see biotic). As a noun, attested 1941 in works of U.S. microbiologist Selman Waksman (1888-1973), discoverer of streptomycin. Earlier the adjective was used in a sense "not from living organisms" in debates over the origins of certain fossils (1860).

antibiotic drug, 1944, from Modern Latin Streptomyces, genus name of the bacterium from which the antibiotic was obtained, from strepto- "twisted" + -mycin, element used in forming names of substances obtained from fungi. First isolated by U.S. microbiologist Selman Abraham Waksman (1888-1973) and others.

antibiotic agent active against bacteria but harmless to most persons, 1929, coined in English by Alexander Fleming (1881-1955), who first recognized its antibiotic properties, from Modern Latin Penicillium notatum (1867), the name of the mould from which it was first obtained, from Latin penicillus "paintbrush" (see pencil (n.)), in reference to the shape of the mould cells.

word-forming element in science, used to form names of antibiotic compounds derived from fungi, from Latinized form of Greek mykēs "fungus, mushroom" (see myco-).