A theater or theatre (also a playhouse) is a structure where theatrical works or plays are performed or other performances such as musical concerts may be produced. While a theater is not required for performance (as in environmental theater or street theater), a theater serves to define the performance and audience spaces. The facility is traditionally organized to provide support areas for performers, the technical crew and the audience members. There are as many types of theaters as there are types of performance. Theaters may be built specifically for a certain types of productions, they may serve for more general performance needs or they may be adapted or converted for use as a theater.