ichthyology, ichthyologic, ichthyological, ichthyologically 1. The branch of zoology that deals with the scientific study of fish. 2. The study of fish and fishlike vertebrates. Ichthyology is the branch of zoology devoted to the study of fish Since there are as many species of fish as all other vertebrates put together, and they have been evolvi... Found on http://www.wordinfo.info/words/index/info/view_unit/2511/2