horn

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun One of the hard, usually permanent structures projecting from the head of certain mammals, such as cattle, sheep, goats, or antelopes, consisting of a bony core covered with a sheath of keratinous material.
• noun A hard protuberance, such as an antler or projection on the head of a giraffe or rhinoceros, that is similar to or suggestive of a horn.
• noun The hard smooth keratinous material forming the outer covering of the horns of cattle or related animals.
• noun A natural or synthetic substance resembling this material.
• noun A container, such as a powder horn, made from a horn.
• noun Something having the shape of a horn, especially.
• noun A horn of plenty; a cornucopia.
• noun Either of the ends of a new moon.
• noun The point of an anvil.
• noun The pommel of a saddle.
• noun An ear trumpet.
• noun A device for projecting sound waves, as in a loudspeaker.
• noun A hollow, metallic electromagnetic transmission antenna with a circular or rectangular cross section.
• noun A wind instrument made of an animal horn.
• noun A brass instrument, such as a trombone or tuba.
• noun A French horn.
• noun A wind instrument, such as a trumpet or saxophone, used in a jazz band.
• noun A usually electrical signaling device that produces a loud resonant sound.
• noun Any of various noisemakers operated by blowing or by squeezing a hollow rubber ball.
• noun Slang A telephone.
• intransitive verb To join without being invited; intrude. Used with in.
• idiom (blow/toot) To brag or boast about oneself.
• idiom (draw/haul) /pull) To restrain oneself; draw back.
• idiom (draw/haul) /pull) To retreat from a previously taken position, view, or stance.
• idiom (draw/haul) /pull) To economize.
• idiom (on the horns of a dilemma) Faced with two equally undesirable alternatives.

from The Century Dictionary.

• To operate upon by means of a horn-press or horning-press. See horn, n., 4 .
• noun An excrescent growth upon the head in certain animals, serving as a weapon of offense or defense. See def. 3.
• noun An antler of a deer.
• noun Hardened and thickened epidermis or cuticle, as that of which nails, claws, and hoofs consist, differing from hair or other cuticular structures chiefly in density and massiveness.
• noun Something made of horn, or like or likened to a horn in position, shape, use, or purpose.
• noun Specifically— A feeler; a tentacle; an antenna; an ovipositor; also, the tuft of feathers upon the head of sundry birds, resembling a horn; a plumicorn, as that of various owls.
• noun A wind-instrument more or less resembling a horn in shape and size, and originally made of horn: as, a hunting-horn; a tin horn. In the simpler forms the horn is used chiefly to give signals, producing single or slightly variable loud tones. The hunting-horn, however, was early elaborated and made capable of producing a variety of calls, fanfares, and simple tnnes. Wood, ivory, and various metals have been used for making horns.
• noun By extension, a musical wind-instrnment of the trumpet class, developed from the hunting-horn (previously modified for use in orchestras under the name corno di caccia), and distinctively called the French horn, having a slender tube of brass or silver, several feet long, gracefully curved upon itself, terminating in a flaring bell, and blown through a mouthpiece of conoidal bore. Its tones are harmonics of the natural tone of the tube, produced by slightly varying the method and pressure of the blowing. Its compass is about four octaves, the series of tones in the two upper octaves being diatonic and partially chromatic. In addition to these primary or open tones, modified or closed tones are produced by inserting the hand into the bell, so as to alter the pitch of an open tone chromatically. The pitch of the fundamental tone, and thus of the whole series of open tones, is altered by detachable crooks, which increase the actual length of the tube. From eight to twelve such crooks are made, pitching the instrument in nearly all the chromatic keys between the second C below middle C and the second Bb below that. The key in which the instrnment is to be set is indicated at the beginning of each piece; but the music is written in the key of C. The pitch of the tube is still further affected by the tuning-slide, which is one of the curves of the tube so arranged that it can be pushed in or out at will. Ventils or valves are sometimes added to the tube to facilitate rapid passages. Horns are the most valuable orchestral instruments of their class. Their tone is mellow, pervasive, and blending, with a peculiar romantic quality. The French horn is sometimes used singly or as a solo instrument, but in orchestras it is nearly always combined in pairs or in quartets, and used both for melodic effects, especially in fanfares and similar figures, and for sustained chords as a harmonic basis for free instrumentation.
• noun A drinking-vessel of the shape of a horn or made of a horn. See drinking-horn.
• noun A long projection, frequently of silver or gold, worn on the forehead by natives of some Asiatic countries.
• noun One of the extremities (cnsps) of the moon when waxing and waning, and hence of any crescent-shaped object.
• noun The horn of a cow or other animal, or, now, any similar case or fiask, used for holding gunpowder; a powderhorn or powder-flask.
• noun plural A head-dress worn during the first half of the fifteenth century, the general shape of which was that of a pair of horns spreading like those of an ox. These head-dresses consisted of stuffs embroidered and set with jewels, or of nets (compare crespine) by which the hair was entirely or almost entirely concealed, a veil covering the whole.
• noun A projecting part of a head-dress, especially of that of women in the fourteenth century.
• noun (J) Eccles., either of the corners or angles made by the front and ends of an altar. In Christian churches, that at the left of the priest when facing the altar is the gospel horn; that at his right, the epistle horn.
• noun In the Bible, a symbol of strength, power, or glory.
• noun In railroad-cars, a part rigidly fastened to the coupler or draw-bar, by means of which the coupler and buffer-springs are connected.
• noun Either of two projections on a side-saddle, serving to support the right leg.
• noun The beak of an anvil.
• noun A branch of a subdivided stream.
• noun Nautical, one of the ends of the crosstrees.