siˈstȯidēə noun plural
Usage: capitalized
Etymology: New Latin, from cyst- + -oidea
: a class of Paleozoic short-stemmed or stemless pelmatozoan echinoderms formerly considered an order of Crinoidea having the body commonly somewhat globular or egg-shaped and enclosed in calcareous plates that are usually pierced by a system of pores possibly respiratory in function