Gill: organ for obtaining oxygen from water.

Gill arch: the bony support for the gill filament and gill rakers.

Gill chamber: the space around the gills enclosed by the opercules.

Gill filament: slender respiratory structures which compose the posterior part of the gill arch where gas exchange occurs.

Gill membrane: membrane along the ventral and posterior margin of the operculum; it is supported by the branchiostegal rays.

Gill opening: the opening on the head covered by the operculum, through which the water used for respiration is expelled.

Gill raker: bony projections on anterior edge of the gill arch.

Gill slits: gill openings.

Alternative forms for gill : gill arch, gill chamber, gill filament, gill membrane, gill opening, gill raker, gill slits, gills.