flue

n. [ Cf. F. flou light, tender, G. flau weak, W. llwch dust. √84. ] Light down, such as rises from cotton, fur, etc.; very fine lint or hair. Dickens. [ 1913 Webster ]

n. [ Cf. OF. flue a flowing, fr. fluer to flow, fr. L. fluere (cf. Fluent); a perh. a corruption of E. flute. ] 1. An inclosed passage way for establishing and directing a current of air, gases, etc.; an air passage; esp.: (a) A compartment or division of a chimney for conveying flame and smoke to the outer air. (b) A passage way for conducting a current of fresh, foul, or heated air from one place to another. (c) (Steam Boiler) A pipe or passage for conveying flame and hot gases through surrounding water in a boiler; -- distinguished from a tube which holds water and is surrounded by fire. Small flues are called fire tubes or simply tubes. [ 1913 Webster ]

2. In an organ flue pipe, the opening between the lower lip and the languet. [ Webster 1913 Suppl. ]

Flue boiler. See under Boiler. --
Flue bridge, the separating low wall between the flues and the laboratory of a reverberatory furnace. --
Flue plate (Steam Boiler), a plate to which the ends of the flues are fastened; -- called also flue sheet, tube sheet, and tube plate. --
Flue surface (Steam Boiler), the aggregate surface of flues exposed to flame or the hot gases. [ 1913 Webster ]

‖n. [ G., a wing. ] (Mus.) 1. A grand piano or a harpsichord, both being wing-shaped. [ archaic ] [ 1913 Webster +PJC ]

2. A flugelhorn. [ PJC ]

n. [ from German flügelhorn. ] A brass instrument resembling a cornet but with a wider bore.
Syn. -- flugelhorn, flügelhorn. [ WordNet 1.5 ]

[ from German flügelhorn. ] n. A brass wind instrument resembling a cornet but with a wider bore, and having three valves.
Syn. -- fluegelhorn. [ WordNet 1.5 ]

n. Fluency. [ Obs. ] Milton. [ 1913 Webster ]

n. [ L. fluentia: cf. F. fluence. See Fluent. ] The quality of being fluent; smoothness; readiness of utterance; volubility. [ 1913 Webster ]

The art of expressing with fluency and perspicuity. Macaulay. [ 1913 Webster ]

a. [ L. fluens, -entis, p. pr. of fluere to flow; cf. Gr. &unr_; to boil over. Cf. Fluctuate, Flux. ] 1. Flowing or capable of flowing; liquid; glodding; easily moving. [ 1913 Webster ]

2. Ready in the use of words; voluble; copious; having words at command; and uttering them with facility and smoothness; as, a fluent speaker; hence, flowing; voluble; smooth; -- said of language; as, fluent speech. [ 1913 Webster ]

With most fluent utterance. Denham. [ 1913 Webster ]

Fluent as the flight of a swallow is the sultan's letter. De Quincey. [ 1913 Webster ]

n. 1. A current of water; a stream. [ Obs. ] [ 1913 Webster ]

2. [ Cf. F. fluente. ] (Math.) A variable quantity, considered as increasing or diminishing; -- called, in the modern calculus, the function or integral. [ 1913 Webster ]