ˌ ̷ ̷ ̷ ̷ˈ ̷ ̷strəˌsī noun plural
Usage: capitalized
Etymology: New Latin, from heter- + Greek ostrakon shell, potsherd — more at ostracon
: a class or other division of ostracoderms with widely separated nares and eyes and with an exoskeleton which may consist of a few large plates or numerous placoid scales