The Collaborative International Dictionary
Suprabranchial
Suprabranchial \Su`pra*bran"chi*al\, a. (Zo["o]l.) Situated above the branchi[ae]; -- applied especially to the upper division of the gill cavity of bivalve mollusks.
Wiktionary
suprabranchial
a. (context zoology English) Situated above the branchiae; applied especially to the upper division of the gill cavity of bivalve mollusks.