Bacteriology is the scientific study of bacteria — the tiny living things, too small to see with the eye, that live almost everywhere. This branch of science asks how bacteria grow, how they change, which ones cause disease, and how we can use them or stop them. It sits next to other “tiny life” sciences: virology is about viruses. Students meet the word in biology class and in medicine. It is a formal, school-and-lab noun. Though actually, a lot of this work now lives under the bigger name “microbiology,” which covers bacteria and other microscopic life together; bacteriology is the more focused piece.