əˈkänchēəm noun
( plural acon·tia -ēə ; or acontiums )
Etymology: New Latin, from Greek akontion javelin, diminutive of akont-, akōn
zoology : one of the free threads continued from the lower ends of the septa of certain actinians, histologically similar to cnidoglandular bands, protruding through the mouth when the animal contracts, and prob. defensive