safety curtain
noun [ C ] uk/ˈseɪf.ti ˌkɜː.tən/ us/ˈseɪf.ti ˌkɝː.t̬ən/
（剧场的）防火帘，防火幕，安全幕
in a theatre, a curtain made of material that will not burn that comes down between the stage and the part where people sit to prevent any possible fire from spreading