The Collaborative International Dictionary of English v.0.48:

Brass \Brass\, n.; pl. Brasses. [OE. bras, bres, AS. br[ae]s;
   akin to Icel. bras cement, solder, brasa to harden by fire,
   and to E. braze, brazen. Cf. 1st & 2d Braze.]
   1. An alloy (usually yellow) of copper and zinc, in variable
      proportion, but often containing two parts of copper to
      one part of zinc. It sometimes contains tin, and rarely
      other metals.
      [1913 Webster]

   2. (Mach.) A journal bearing, so called because frequently
      made of brass. A brass is often lined with a softer metal,
      when the latter is generally called a white metal lining.
      See Axle box, Journal Box, and Bearing.
      [1913 Webster]

   3. Coin made of copper, brass, or bronze. [Obs.]
      [1913 Webster]

            Provide neither gold, nor silver, nor brass in your
            purses, nor scrip for your journey.   --Matt. x. 9.
      [1913 Webster]

   4. Impudence; a brazen face. [Colloq.]
      [1913 Webster]

   5. pl. Utensils, ornaments, or other articles of brass.
      [1913 Webster]

            The very scullion who cleans the brasses.
                                                  --Hopkinson.
      [1913 Webster]

   6. A brass plate engraved with a figure or device.
      Specifically, one used as a memorial to the dead, and
      generally having the portrait, coat of arms, etc.
      [1913 Webster]

   7. pl. (Mining) Lumps of pyrites or sulphuret of iron, the
      color of which is near to that of brass.
      [1913 Webster]

   Note: The word brass as used in Sculpture language is a
         translation for copper or some kind of bronze.
         [1913 Webster]

   Note: Brass is often used adjectively or in self-explaining
         compounds; as, brass button, brass kettle, brass
         founder, brass foundry or brassfoundry.
         [1913 Webster]

   Brass band (Mus.), a band of musicians who play upon wind
      instruments made of brass, as trumpets, cornets, etc.

   Brass foil, Brass leaf, brass made into very thin sheets;
      -- called also Dutch gold.
      [1913 Webster]

WordNet (r) 3.0 (2006):

brass
    n 1: an alloy of copper and zinc
    2: a wind instrument that consists of a brass tube (usually of
       variable length) that is blown by means of a cup-shaped or
       funnel-shaped mouthpiece [syn: brass, brass instrument]
    3: the persons (or committees or departments etc.) who make up a
       body for the purpose of administering something; "he claims
       that the present administration is corrupt"; "the governance
       of an association is responsible to its members"; "he quickly
       became recognized as a member of the establishment" [syn:
       administration, governance, governing body,
       establishment, brass, organization, organisation]
    4: impudent aggressiveness; "I couldn't believe her boldness";
       "he had the effrontery to question my honesty" [syn:
       boldness, nerve, brass, face, cheek]
    5: an ornament or utensil made of brass
    6: the section of a band or orchestra that plays brass
       instruments [syn: brass section, brass]
    7: a memorial made of brass [syn: brass, memorial tablet,
       plaque]

Moby Thesaurus II by Grady Ward, 1.0:

365 Moby Thesaurus words for "brass":
   ADC, CO, Establishment, German band, OD, Philharmonic, VIP, aide,
   aide-de-camp, alpenhorn, alphorn, althorn, alto horn, arch,
   aristocracy, aureate, ballad horn, band, baritone, baron, barons,
   barrow, bass horn, big band, big gun, big man, big name, bigwig,
   blunt, board, board of directors, board of regents,
   board of trustees, boodle, boundary stone, brashness, brass band,
   brass choir, brass hat, brass quintet, brass section, brass wind,
   brass-wind instrument, brasses, brassy, brazen, brazen boldness,
   bread, brigadier, brigadier general, bronze, bronzy, bucks, bugle,
   bugle horn, bust, cabbage, cabinet, cadre, cairn,
   callithumpian band, captain, celebrity, cenotaph,
   chamber orchestra, cheek, chicken colonel, chief of staff, chips,
   chutzpah, clarion, colonel, column, combo, commandant, commander,
   commander in chief, commanding officer, commissioned officer,
   company officer, concert band, confidence, copper, coppery, cornet,
   cornet-a-pistons, corno di caccia, cornopean, council, cream,
   cromlech, cross, crust, cup, cupreous, cuprous, cyclolith, desks,
   dignitary, dignity, dinero, directorate, directory, dixieland band,
   do-re-mi, dolmen, double-bell euphonium, dough, effrontery, elder,
   elite, ensemble, establishment, euphonium, exec, executive arm,
   executive committee, executive hierarchy, executive officer, face,
   father, ferrous, ferruginous, field marshal, field officer, figure,
   first lieutenant, five-star general, footstone, four-star general,
   gall, gamelan orchestra, gelt, general, general officer,
   generalissimo, gilt, gold, gold-filled, gold-plated, golden,
   governing board, governing body, grave, gravestone, grease,
   great man, green, green stuff, group, headstone, helicon, heroics,
   hoarstone, horn, hubris, hunting horn, important person,
   improvidence, imprudence, impudence, indiscretion, infrastructure,
   injudiciousness, inscription, insolence, interests,
   interlocking directorate, iron, ironlike, jack, jazz band, jemadar,
   jug band, junior officer, kale, key trumpet, lead, leaden,
   lieutenant, lieutenant colonel, lieutenant general, lion, lituus,
   lords of creation, lur, magnate, major, major general, man of mark,
   management, marechal, marker, marshal, mausoleum, mazuma, megalith,
   mellophone, memento, memorial, memorial arch, memorial column,
   memorial statue, memorial stone, menhir, mercurial, mercurous,
   military band, mogul, monolith, monument, moolah, mopus, mound,
   nabob, name, necrology, nerve, nickel, nickelic, nickeline,
   nobility, notability, notable, obelisk, obituary, officer,
   oil of palms, ointment, one-star general, oof, ooftish, ophicleide,
   orchestra, orchestral horn, orderly officer, overboldness,
   overcarelessness, overconfidence, overlapping, oversureness,
   overweeningness, panjandrum, person of renown, personage,
   personality, pewter, pewtery, pillar, pillar of society, plaque,
   pocket trumpet, post horn, power, power elite, power structure,
   presumption, prize, pyramid, quartet, quicksilver, quintet,
   ragtime band, rashness, reliquary, remembrance, rhino, ribbon,
   risaldar, rock-and-roll group, rocks, rostral column, rudeness,
   ruling circle, ruling circles, ruling class, sachem, sackbut,
   saxhorn, saxtuba, senior officer, serpent, sextet, shaft,
   shavetail, shekels, shrine, silver, silver-plated, silvery,
   simoleons, sirdar, skiffle band, slide trombone, sliphorn,
   somebody, something, sousaphone, spondulics, staff officer, steel,
   steel band, steely, steering committee, stela, stone, street band,
   string band, string choir, string orchestra, string quartet,
   strings, stupa, subahdar, subaltern, sublieutenant, sugar,
   swing band, symphony, symphony orchestra, tablet, temerariousness,
   temerity, tenor tuba, testimonial, the Old Man, the administration,
   the best, the best people, the brass, the executive, the great,
   the needful, the people upstairs, the top, three-star general, tin,
   tinny, tomb, tombstone, top brass, top people, tope, trio, tromba,
   trombone, trophy, trumpet, tuba, two-star general, tycoon,
   unchariness, unwariness, upper class, upper crust, valve trombone,
   valve trumpet, very important person, waits, wampum, woodwind,
   woodwind choir, woodwind quartet, woodwinds, worthy



Easton's 1897 Bible Dictionary:

Brass
   which is an alloy of copper and zinc, was not known till the
   thirteenth century. What is designated by this word in Scripture
   is properly copper (Deut. 8:9). It was used for fetters (Judg.
   16:21; 2 Kings 25:7), for pieces of armour (1 Sam. 17:5, 6), for
   musical instruments (1 Chr. 15:19; 1 Cor. 13:1), and for money
   (Matt. 10:9).

     It is a symbol of insensibility and obstinacy in sin (Isa.
   48:4; Jer. 6:28; Ezek. 22:18), and of strength (Ps. 107:16;
   Micah 4:13).

     The Macedonian empire is described as a kingdom of brass (Dan.
   2:39). The "mountains of brass" Zechariah (6:1) speaks of have
   been supposed to represent the immutable decrees of God.

     The serpent of brass was made by Moses at the command of God
   (Num. 21:4-9), and elevated on a pole, so that it might be seen
   by all the people when wounded by the bite of the serpents that
   were sent to them as a punishment for their murmurings against
   God and against Moses. It was afterwards carried by the Jews
   into Canaan, and preserved by them till the time of Hezekiah,
   who caused it to be at length destroyed because it began to be
   viewed by the people with superstitious reverence (2 Kings
   18:4). (See NEHUSHTAN.)

     The brazen serpent is alluded to by our Lord in John 3:14, 15.
   (See SERPENT.)