The Collaborative International Dictionary
Pleurobranch
Pleurobranch \Pleu"ro*branch\, n. [See Pleuro-, and Branchia.] (Zo["o]l.) Any one of the gills of a crustacean that is attached to the side of the thorax.
Wiktionary
pleurobranch
n. (context zoology English) Any of the gills of a crustacean that are attached to the side of the thorax.