orchestra  
noun uk/ˈɔː.kɪ.strə/ us/ˈɔːr.kə.strə/
  (MUSIC)      
 B1 [ C, + sing/pl verb ]管弦乐队 
a large group of musicians who play many different instruments together and are led by a conductor
  She's a cellist in the City of Birmingham Symphony Orchestra. 她是伯明翰交响乐团的大提琴手。 
 - More examples
 - The orchestra was conducted by Mira Shapur.
 - The orchestra is to perform its last ever concert tomorrow night at the Albert Hall.
 - The orchestra performed the Rite of Spring with great spirit.
 - The orchestra played superbly.
 - We admired the sureness of the orchestra's playing.
 
  (THEATRE)    
the orchestra[ S ] US (UK the stalls) 正厅前排座位
the seats on the main floor of a theatre or cinema, not at a higher level