the respiratory organ of aquatic animals, as fish, that breathe oxygen dissolved in water.

Also called lamella. one of the radiating vertical plates on the underside of the cap of an agaric mushroom.

ground ivy.

to gut or clean (fish). ?

to catch (fish) by the gills in a gill net.

green or white around the gills, somewhat pale, as from being sickly, nervous

or frightened

When he heard how much the bill was, he looked a little green around the gills.

to the gills

Informal . fully; completely; totally

After that big meal we were all stuffed to the gills.