germ
n.a tiny living thing that can cause disease. You cannot see them without a microscope, but they are everywhere.
n.a microorganism, especially one which causes disease. Often used in a non-technical sense to refer to bacteria or viruses that spread illness.
“Wash your hands to get rid of germs.”
“The school nurse taught the children that covering their mouths when they cough prevents germs from spreading to their classmates.”
“While most people associate the word with illness, only a small fraction of known germs actually cause disease in humans, with many others playing vital roles in the ecosystem.”
Commonly used in the plural form when referring to hygiene or illness.
From Middle French germe, from Latin germen (“bud, seed, embryo”). Doublet of germen.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.