Origin: Greek suffix -ology
Entomology has 2 different meanings across 1 category:
the branch of zoology that studies insects
"She decided to major in entomology after spending her summers collecting beetles in the local forests."
The scientific study of insects, and (informal) of other arthropods (and occasionally other invertebrates).
"After hours of sorting through the garden leaves to identify every beetle and spider she found, her passion for entomology finally paid off when she discovered a rare species."