pə|ris(ˌ)kōˌekəˈnȯidə noun plural
Usage: capitalized
Etymology: New Latin perischo- (from Greek perischesis surrounding, from periechein, perischein to surround — from peri- + echein, schein to have, hold — + -sis ) + echin- + -oida — more at scheme
: a large order of regular Paleozoic Echinoidea