[1] : The Collaborative International Dictionary of English v.0.48

horn \horn\ h^orn, n. as. horn; akin to d. horen, hoorn,
   g., icel., sw.,  dan. horn, goth. ha'urn, w., gael.,  ir.
   corn, l. cornu, gr. ke`ras, and perh. also to e. cheer,
   cranium, cerebral; cf. skr. ,ciras head. cf. carat,
   corn on the foot, cornea, corner, cornet,
   cornucopia, hart.
   1. a hard, projecting, and usually pointed organ, growing
      upon the heads of certain animals, esp. of the ruminants,
      as cattle, goats, and the like. the hollow horns of the ox
      family consist externally of true horn, and are never
      shed.
      1913 webster

   2. the antler of a deer, which is of bone throughout, and
      annually shed and renewed.
      1913 webster

   3. zool. any natural projection or excrescence from an
      animal, resembling or thought to resemble a horn in
      substance or form; esp.:
      a a projection from the beak of a bird, as in the
          hornbill.
      b a tuft of feathers on the head of a bird, as in the
          horned owl.
      c a hornlike projection from the head or thorax of an
          insect, or the head of a reptile, or fish.
      d a sharp spine in front of the fins of a fish, as in
          the horned pout.
          1913 webster

   4. bot. an incurved, tapering and pointed appendage found
      in the flowers of the milkweed asclepias.
      1913 webster

   5. something made of a horn, or in resemblance of a horn; as:
      a a wind instrument of music; originally, one made of a
          horn of an ox or a ram; now applied to various
          elaborately wrought instruments of brass or other
          metal, resembling a horn in shape. "wind his horn
          under the castle wall." --spenser. see french horn,
          under french.
      b a drinking cup, or beaker, as having been originally
          made of the horns of cattle. "horns of mead and ale."
          --mason.
      c the cornucopia, or horn of plenty. see cornucopia.
          "fruits and flowers from amalthaea's horn."
          --milton.
      d a vessel made of a horn; esp., one designed for
          containing powder; anciently, a small vessel for
          carrying liquids. "samuel took the hornof oil and
          anointed him david." --1 sam. xvi. 13.
      e the pointed beak of an anvil.
      f the high pommel of a saddle; also, either of the
          projections on a lady's saddle for supporting the leg.
      g arch. the ionic volute.
      h naut. the outer end of a crosstree; also, one of the
          projections forming the jaws of a gaff, boom, etc.
      i carp. a curved projection on the fore part of a
          plane.
      j one of the projections at the four corners of the
          jewish altar of burnt offering. "joab . . . caught
          hold on the horns of the altar." --1 kings ii. 28.
          1913 webster

   6. one of the curved ends of a crescent; esp., an extremity
      or cusp of the moon when crescent-shaped.
      1913 webster

            the moon
            wears a wan circle round her blunted horns.
                                                  --thomson.
      1913 webster

   7. mil. the curving extremity of the wing of an army or of
      a squadron drawn up in a crescentlike form.
      1913 webster

            sharpening in mooned horns
            their phalanx.                        --milton.
      1913 webster

   8. the tough, fibrous material of which true horns are
      composed, being, in the ox family, chiefly albuminous,
      with some phosphate of lime; also, any similar substance,
      as that which forms the hoof crust of horses, sheep, and
      cattle; as, a spoon of horn.
      1913 webster

   9. script. a symbol of strength, power, glory, exaltation,
      or pride.
      1913 webster

            the lord is . . . the horn of my salvation. --ps.
                                                  xviii. 2.
      1913 webster

   10. an emblem of a cuckold; -- used chiefly in the plural.
       "thicker than a cuckold's horn." --shak.
       1913 webster

   11. the telephone; as, on the horn. slang
       pjc

   12. a body of water shaped like a horn; as, the golden horn
       in istanbul.
       pjc

   horn block, the frame or pedestal in which a railway car
      axle box slides up and down; -- also called horn plate.
      

   horn of a dilemma. see under dilemma.

   horn distemper, a disease of cattle, affecting the internal
      substance of the horn.

   horn drum, a wheel with long curved scoops, for raising
      water.

   horn lead chem., chloride of lead.

   horn maker, a maker of cuckolds. obs. --shak.

   horn mercury. min. same as horn quicksilver below.

   horn poppy bot., a plant allied to the poppy glaucium
      luteum, found on the sandy shores of great britain and
      virginia; -- called also horned poppy. --gray.

   horn pox med., abortive smallpox with an eruption like
      that of chicken pox.

   horn quicksilver min., native calomel, or bichloride of
      mercury.

   horn shell zool., any long, sharp, spiral, gastropod
      shell, of the genus cerithium, and allied genera.

   horn silver min., cerargyrite.

   horn slate, a gray, siliceous stone.

   to pull in one's horns, to haul in one's horns, to
      withdraw some arrogant pretension; to cease a demand or
      withdraw an assertion. colloq.

   to raise the horn, or to lift the horn script., to
      exalt one's self; to act arrogantly. "'gainst them that
      raised thee dost thou lift thy horn?" --milton.

   to take a horn, to take a drink of intoxicating liquor.
      low
      1913 webster
see also:
carat corn cornea corner cornet cornucopia 
hart asclepias french horn french telephone 
horn block horn plate horn of a dilemma dilemma horn distemper 
horn drum horn lead horn maker horn mercury horn quicksilver 
horn poppy glaucium luteum horned poppy horn pox horn shell 
cerithium horn silver horn slate to pull in one's horns to haul in one's horns 
to raise the horn to lift the horn to take a horn 

[2] : The Collaborative International Dictionary of English v.0.48

horn \horn\, v. t.
   1. to furnish with horns; to give the shape of a horn to.
      1913 webster

   2. to cause to wear horns; to cuckold. obs. --shak.
      1913 webster

[3] : WordNet (r) 2.0

horn
     n 1: a noisemaker as at parties or games that makes a loud
          noise when you blow through it
     2: one of the bony outgrowths on the heads of certain ungulates
     3: a noise made by the driver of an automobile to give warning;
     4: a high pommel of a western saddle usually metal covered
        with leather syn: saddle horn
     5: a brass musical instrument with a brilliant tone; has a
        narrow tube and a flared bell and is played by means of
        valves syn: cornet, trumpet, trump
     6: any outgrowth from the head of an organism that resembles a
        horn
     7: the material mostly keratin that covers the horns of
        ungulates and forms hooves and claws and nails
     8: an alarm device that makes a loud warning sound
     9: a brass musical instrument consisting of a conical tube that
        is coiled into a spiral and played by means of valves
        syn: french horn
     10: a device on an automobile for making a warning noise syn: automobile
         horn, car horn, motor horn, hooter
     v : stab or pierce with a horn or tusk; "the rhino horned the
         explorer" syn: tusk
see also:
saddle horn cornet trumpet trump french horn automobile horn 
car horn motor horn hooter tusk 

[4] : Moby Thesaurus II by Grady Ward, 1.0

161 moby thesaurus words for "horn":
   klaxon, mayday, sos, acoustical network, aerophone, air-raid alarm,
   alarm, alarm bell, alarm clock, alarm signal, alarum, alert,
   all clear, alpenhorn, alphorn, althorn, alto horn, ballad horn,
   baritone, bass horn, beacon, bell, bellyband, blinking light,
   boiler factory, boiler room, brass choir, brass wind,
   brass-wind instrument, brasses, bugle, bugle horn, bull-roarer,
   burglar alarm, buzzer, capacitor speaker, catcall, cherry bomb,
   cinch, clack, clacker, clapper, clarion, coaxial speaker, cone,
   cornet, cornet-a-pistons, corno di caccia, cornopean, cracker,
   cricket, crossover network, crostarie, diaphragm, double reed,
   double-bell euphonium, dynamic speaker, earphone,
   electrodynamic speaker, electromagnetic speaker,
   electrostatic speaker, embouchure, euphonium,
   excited-field speaker, fiery cross, fire alarm, fire bell,
   fire flag, firecracker, five-minute gun, flashing light, fog bell,
   fog signal, foghorn, full-fidelity speaker, gale warning, girt,
   girth, gore, headphone, headset, helicon, high-fidelity speaker,
   high-frequency speaker, hooter, hue and cry, hunting horn,
   hurricane warning, jockey, key, key trumpet, lighthouse, lip,
   lituus, loudspeaker, low-frequency speaker, lur, mellophone,
   midrange speaker, monorange speaker, mouthpiece,
   moving-coil speaker, noisemaker, note of alarm, occulting light,
   ophicleide, orchestral horn, permanent magnet speaker, pipe,
   pocket trumpet, police whistle, pommel, post horn, rattle,
   rattlebox, reed, sackbut, saxhorn, saxtuba, serpent,
   signal of distress, siren, slide, slide trombone, sliphorn,
   small-craft warning, snapper, sousaphone, speaker, speaker system,
   speaker unit, steam whistle, still alarm, stirrup, storm cone,
   storm flag, storm warning, surcingle, tenor tuba, ticktack, tocsin,
   tooter, triaxial speaker, tromba, trombone, trumpet, tuba, tusk,
   tweeter, two-minute gun, upside-down flag, valve, valve trombone,
   valve trumpet, voice coil, whistle, whizgig, whizzer, wind,
   wind instrument, woofer

[5] : Easton's 1897 Bible Dictionary

horn
   trumpets were at first horns perforated at the tip, used for
   various purposes josh. 6:4,5.
   
     flasks or vessels were made of horn 1 sam. 16:1, 13; 1 kings
   1:39.
   
     but the word is used also metaphorically to denote the
   projecting corners of the altar of burnt offerings ex. 27:2
   and of incense 30:2. the horns of the altar of burnt offerings
   were to be smeared with the blood of the slain bullock 29:12;
   lev. 4:7-18. the criminal, when his crime was accidental, found
   an asylum by laying hold of the horns of the altar 1 kings
   1:50; 2:28.
   
     the word also denotes the peak or summit of a hill isa. 5:1,
   where the word "hill" is the rendering of the same hebrew word.
   
     this word is used metaphorically also for strength deut.
   33:17 and honour job 16:15; lam. 2:3. horns are emblems of
   power, dominion, glory, and fierceness, as they are the chief
   means of attack and defence with the animals endowed with them
   dan. 8:5, 9; 1 sam. 2:1; 16:1, 13; 1 kings 1:39; 22:11; josh.
   6:4, 5; ps. 75:5, 10; 132:17; luke 1:69, etc.. the expression
   "horn of salvation," applied to christ, means a salvation of
   strength, or a strong saviour luke 1:69. to have the horn
   "exalted" denotes prosperity and triumph ps. 89:17, 24. to
   "lift up" the horn is to act proudly zech. 1:21.
   
     horns are also the symbol of royal dignity and power jer.
   48:25; zech. 1:18; dan. 8:24.
   

French Horn >> F Words
French Horn, definition of term: French Horn
french+horn_pag1.html

English Horn >> E Words
English Horn, definition of term: English Horn
english+horn_pag1.html

Car Horn >> C Words
Car Horn, definition of term: Car Horn
car+horn_pag1.html

Basset Horn >> B Words
Basset Horn, definition of term: Basset Horn
basset+horn_pag1.html