tetrabranchiate

adjective

1. belonging or pertaining to the Nautiloidea (Tetrabranchiata), a subclass or order of cephalopods with four gills, including the pearly nautilus and numerous fossil forms.

adjective (ˌtɛtrəˈbræŋkɪɪt, -ˌeɪt)

1. of, relating to, or belonging to the Tetrabranchiata, a former order of cephalopod molluscs having four gills and including the pearly nautilus

noun (ˌtɛtrəˈbræŋkɪˌeɪt)

2. any mollusc belonging to the Tetrabranchiata