orchestra pit

US /ˈɔːr.kɪ.strə pɪt/
UK /ˈɔːr.kɪ.strə pɪt/
"orchestra pit" picture
1.

a sunken area in front of a stage where an orchestra plays, typically in a theater or opera house

:
The conductor stood in the orchestra pit, ready to begin the opera.
The sound from the orchestra pit filled the entire theater.