gill

Other forms: gills

A gill is the body part that helps a fish breathe underwater. In fish and other aquatic creatures, their gills are equivalent to our lungs.

Fish and some amphibians need to breathe the oxygen in water to live, and they use their gills for this. Gills are the main organs of respiration for animals that live in or under the water. The root of gill is uncertain, but it may be related to the Old Norse gjölnar, "gills," and rooted in the Proto-Indo-European ghel-una, or "jaw."

Definitions of gill

1. noun

   respiratory organ of aquatic animals that breathe oxygen dissolved in water
   synonyms: branchia

   types:

   ctenidium

   comb-like respiratory structure serving as the gill of certain mollusks

   ceras

   one of the often brightly colored and branching hornlike structures on the back of the nudibranch (and other related mollusks) that serve as gills

   external gill

   occurs in some mollusks and in tadpoles and other immature amphibians

   type of:

   respiratory organ

   any organ involved in the process of respiration
2. noun

   any of the radiating leaflike spore-producing structures on the underside of the cap of a mushroom or similar fungus
   synonyms: lamella

   type of:

   plant organ

   a functional and structural unit of a plant or fungus