"of or pertaining to microbes," 1879, from Modern Latin microbion (see microbe) + -al (1).
Entries linking to microbial
microbe n.
popular name for a bacterium or other extremely small living being, 1878, from French microbe, "badly coined ... by Sédillot" [Weekley] in 1878 from Latinized form of Greek mikros "small" (see micro-) + bios "life" (from PIE root *gwei- "to live"). Intended to mean literally "a small living being," the use of bios is incorrect, as in modern science generally (see bio-); in Greek the compound would mean "short-lived."
-al 1
suffix forming adjectives from nouns or other adjectives, "of, like, related to, pertaining to," Middle English -al, -el, from French or directly from Latin -alis (see -al (2)).