ˌekēyəˈrȯidēə noun plural
Usage: capitalized
Etymology: New Latin, from Echiurus + -oidea
: a group of marine worms of obscure position though commonly classed as a division of Gephyrea and distinguished by a sensitive but nonretractile proboscis overlying the mouth which in some forms (as some worms of the genus Bonellia ) may attain great size