Noun

Singular brass

Plural countable and uncountable; plural brasses

brass (countable and uncountable; plural brasses)

1. A metallic alloy of copper and zinc used in many industrial and plumbing applications.
2. (music) A class of wind instruments, usually made of metal (such as brass), that use vibrations of the player's lips to produce sound.
3. Spent shell casings (usually made of brass); the part of the cartridge left over after bullets have been fired.
4. The colour of brass.

   brass colour:

5. (military) (used as a singular or plural noun) High-ranking officers.

   The brass are not going to like this.

   The brass is not going to like this.

6. (informal) A brave or foolhardy attitude.

   You've got a lot of brass telling me to do that!

7. (slang; also brass in pocket) Money.
8. (slang; from brass nail; countable) A prostitute.

Brass is any alloy of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties. In comparison, bronze is principally an alloy of copper and tin. Despite this distinction some types of brasses are called bronzes and vice-versa. Brass is a substitutional alloy. It is used for decoration for its bright gold-like appearance; for applications where low friction is required such as locks, gears, bearings, doorknobs, ammunition, and valves; for plumbing and electrical applications; and extensively in musical instruments such as horns and bells for its acoustic properties. It is also used in zippers. Because it is softer than most other metals in general use, brass is often used in situations where it is important that sparks not be struck, as in fittings and tools around explosive gases.

Brass has a muted yellow color, somewhat similar to gold. It is relatively resistant to tarnishing, and is often used as decoration and for coins. In antiquity, polished brass was often used as a mirror.

Although forms of brass have been in use since prehistory, its true nature as a copper-zinc alloy was not understood until the post medieval period because the zinc vapour which reacted with copper to make brass was not recognised as a metal. Many references to "brass" appearing throughout the King James Bible are thought to signify another bronze alloy, or copper, rather than the strict modern definition of brass. The earliest brasses may have been natural alloys made by smelting zinc-rich copper ores. By the Roman period brass was being deliberately produced from metallic copper and zinc minerals using the cementation process and variations on this method continued until the mid 19th century. It was eventually replaced by speltering, the direct alloying of copper and zinc metal which was introduced to Europe in the 16th century.