It’s a classic line, “Don’t eat that now, it has germs on it!” It, of course, is food that has perhaps fallen on the floor, slipped from a plate onto a roadside picnic table, or been shared with the family pet. The culprit called a germ, from Latin germen, “bud,” is a nontechnical term describing a living organism, especially one not visible to the naked eye, that is capable of causing disease. A term that has a similar meaning but is equally nontechnical is microbe, derived from the Greek prefix mikro-, “small,” and bios, “life.” For situations that demand the meaning carried by germ and microbe but need the added benefit of technical rigor, the term to choose is pathogen. Derived from Greek pathos, “suffering” and the suffix -gen, “producer,” pathogen describes an agent that causes disease, especially a bacterium, fungus, or other microorganism. The term microorganism, built from the prefix micro-, “small” and the noun organism, is a general term that describes all one-celled microscopic organisms, both disease-causing and benign.
