Cnidariology is a sub-discipline of invertebrate zoology that studies the cnidarians. Invertebrate zoology is concerned with the invertebrates. Invertebrates are animals that lack a vertebral column (a backbone). Since there are a number of invertebrate species there are taxonomic-based sub-disciplines of invertebrate zoology, particularly arthropodology (the study of arthropods), cnidariology, and helminthology (the study of helminths).
Cnidariology deals with studying the cnidarians. Cnidarians are those belonging to phylum Cnidaria. They include the jellyfishes, sea anemones, corals, hydras, etc. They are characterized primarily by possessing cnidae, i.e. specialized cellular structures that fire off thread-like tubules producing a stinging effect.
An expert on cnidariology is called cnidariologist. A cnidariologist would be concerned and responsible in conducting research in cnidarians. The research may be associated with the identification and classification of cnidarian species. It may also be about their distribution, conservation, and ecological relationship of the cnidarians to other living things and their environment. The research may also encompass other related fields such as genetics, evolution, and medical importance of cnidarians. An example of a work in cnidariology is that of Alfred G. Mayer, an American marine zoologist who documented his studies on various species of jellyfish around the world through his book entitled Medusae of the World (1910).