gill
noun
1.
a British imperial capacity unit (liquid or dry) equal to 5 fluid ounces or 142.066 cubic centimeters
2.
a United States liquid unit equal to 4 fluid ounces
3.
any of the radiating leaflike spore-producing structures on the underside of the cap of a mushroom or similar fungus
4.
respiratory organ of aquatic animals that breathe oxygen dissolved in water