-oi·dea \ˈȯidēə\noun plural suffix or-oi·da\-də\; or-oi·dei\-dēˌī\ Etymology:-oidea, New Latin, from Latin -oïdes -oid + -ea, neuter plural of -eus -eous; -oida, New Latin, from Latin -oïdes; -oidei, New Latin, from Latin -oïdes + -ei, masculine plural of -eus -eous : animals characterized by or of the nature of — in names of higher taxa in zoology < Echinoidea > < Hydroida > < Ganoidei >