Entomology is the study of insects. If you want to know all about ants, roaches, scorpions, and skeeters, entomology is for you.
From the Greek word for “knowledge,” the suffix -logy literally means “the study of,” and you see it often. Theology is the study of divine beings, anthropology is the study of human cultures, psychology is the study of the mind. Add the Greek prefix entomon, for insect, and you have the branch of biology that focuses on bugs.