n. The breathing-organ of any animal that lives in the water.n. Specifically, an organ in aquatic animals for the aërification of the blood through the medium of water; the respiratory apparatus of any animal that breathes the air which is mixed with water; by extension, a branchia, as of any invertebrate and of the ichthyopsidan vertebrates. See branchiæ.n. Some part like or likened to a gill.n. One of a number of radiating plates on the under side of the cap or pileus of a mushroom.n. In entomology, the branchiæ or external breathing-organs of certain insectlarvæ.To catch (fish) by the gills, as by means of a gill-net: as, gilled fish.[In allusion to the parallel rows of filaments in a fish's gills.] In making worsted yarn, to make the fibers level and parallel with each other by drawing them through a gilling-machine.To display the gills in swimming with the head partly out of water: as, mackerel go along gilling.n. A narrow valley; a ravine, especially one with a rapid stream running through it.n. A corrugation or fold; a hollow, as in a sheet of metal.n. A frame with a pair of wheels used for conveying timber.n. Same as gill-frame.n. A liquid measure, one fourth of a pint in the British and United States systems.n. A pint of ale.n. A girl; a sweetheart: used in familiarity or contempt, as either a proper or a common noun.n. [Short for gill-creep-by-the-ground, or gillrun-over-the-ground, homely names for the plant, in which gill is a familiar application of the feminine name.] The ground-ivy, Nepeta Glechoma.n. Same as gill-beer.n. An English penny or quarter bit.n. A fellow or ‘cove’: as, a queer gill.