A fish breathes by swallowing water and passing it through gill slits on each side of its head. Blood-filled filaments on the gills extract oxygen from the water as it flows through.
gill 1
(gĭl)n.
1. Zoology The respiratory organ of most aquatic animals that obtain oxygen from water, consisting of a filamentous structure of vascular membranes across which dissolved gases are exchanged.
2.
a. often gills The wattle of a bird.
b. gills Informal The area around the chin and neck.
3. Botany One of the thin, platelike structures on the underside of the cap of a mushroom or similar fungus.
v. gilled, gill·ing, gills
v.tr.
1. To catch (fish) in a gill net.
2. To gut or clean (fish).
v.intr.
Idiom: To become entangled in a gill net. Used of fish.
to the gills Informal
As full as possible; completely.
[Middle English gile, of Scandinavian origin.]
gilled adj.
gill 2
(jĭl)n. Abbr. gi or gi.
1. A unit of volume or capacity in the US Customary System, used in liquid measure, equal to 1/4 of a pint or four ounces (118 milliliters).
2. A unit of volume or capacity, used in dry and liquid measure, equal to 1/4 of a British Imperial pint (142 milliliters).
[Middle English gille, from Old French, wine measure, from Late Latin gillō, vessel for cooling liquids.]
gill 3
(gĭl)n. Chiefly British
1. A ravine.
2. A narrow stream.
[Middle English gille, from Old Norse gil.]
gill 4
also jill or Gill (jĭl)n. Obsolete
A girl, often one's sweetheart.
[Middle English gille, from Gille, a woman's name.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.