the.com/brass section

means The group of brass instruments—trumpets, trombones, French horns, tubas—that plays together in an orchestra, band, or ensemble, usually the loudest and most triumphant voice in the room.

from Brass simply names the metal: an alloy of copper and zinc known and worked since antiquity, prized for being both strong and bright-sounding when shaped into tubes and bells. 'Section' comes from Latin sectio, 'a cutting,' from secare, 'to cut'—the orchestra conceptually cut into its component parts (strings, woodwinds, brass, percussion). The phrase itself is a practical 19th/20th-century musical label, not a word with its own secret story—it just means 'the part made of brass instruments,' grouped together because they're played with buzzing lips against a metal mouthpiece rather than reeds or strings, and because they tend to need their own rehearsal, their own sheet music, and their own warning before the cymbals crash.