The word "brangchiostegous" is a term used in zoology to describe fish with gill covers that are modified into armored plates. It is pronounced /ˌbræŋkiəʊˈstiːɡəs/ with emphasis on the second syllable. The spelling of this word is derived from Greek root words- "brankhia" meaning gill and "stegos" meaning covering. The "-ous" at the end is a suffix indicating possession or full of, thus "brangchiostegous" literally means "possessing armor-like gill covers". Due to its complex spelling and pronunciation, this term is mostly used within academia and is unfamiliar to the general population.
Gill covering-applied to certain bones or bent rays which support the membrane covering and protecting the gills of fishes.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.