the.com/concert hall

means A large purpose-built room designed and shaped so that live music — especially unamplified acoustic music — carries clearly and beautifully to every seat.

from 'Concert' traces back through French 'concert' to Italian 'concerto,' itself rooted in Latin 'concertare' — to contend or strive together, from com- ('together') and certare ('to fight, contend, strive'). The sense shifted from 'striving together' to 'performing together in harmony,' which tells you something quiet about how ensembles actually work. 'Hall' is far older and plainer, from Old English 'heall,' a large covered space — originally just the big room in a lord's house where everyone gathered. Put together, the phrase is young by comparison, a straightforward 18th/19th-century label for buildings raised specifically to let that 'striving together' be heard properly.