-ical

(Latin: from -icalis, a suffix that forms adjectives from nouns; of or having to do with; having the nature of; constituting or being; containing or made up of; made by or caused by; like, characteristic of; art or system of thought; chemical terms)

encyclical (s) (noun), encyclicals (pl)
entomological (adjective), more entomological, most entomological
1. A reference to the study of insects or some aspect of insect studies.
2. Of or relating to the biological science of bugs.