The building blocks of English

Affixes

branchio-

Gills.

Greek brankhia, gills.

The branchia are the gills of fish and some invertebrate animals; the adjective relating to them is branchial. A branchiopod (Greek pous, pod‑, foot) is a member of a class of crustaceans (the Branchiopoda) that includes water fleas and fairy shrimps, which have gills on the feet; the adjective branchiostegal (Greek stegē, covering) relates to the covering of gills.