-ēəm noun
( plural glochid·ia -ēə)
Etymology: New Latin, from Greek glōchis projecting point + New Latin -idium — more at gloss (explanation)
1. : a barbed hair or spine (as on the massulae of a water fern or on some cacti)
2. : a larval freshwater mussel of the family Unionidae that hatches in the gill cavity of the parent mussel, is subsequently discharged into the water, and attaches itself as an external parasite to the gills or fins or other parts of fish