The noun brass has 7 senses (first 5 from tagged texts)
1. (11) brass -- (an alloy of copper and zinc)
2. (2) brass, brass instrument -- (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)
3. (1) administration, governance, governing body, establishment, brass, organization, organisation -- (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")
4. (1) boldness, nerve, brass, face, cheek -- (impudent aggressiveness; "I couldn't believe her boldness"; "he had the effrontery to question my honesty")
5. (1) brass -- (an ornament or utensil made of brass)
6. brass section, brass -- (the section of a band or orchestra that plays brass instruments)
7. brass, memorial tablet, plaque -- (a memorial made of brass)