Material that hangs in a window or other opening as a decoration, shade, or screen. Something that functions as or resembles a screen, cover, or barrier: the curtain of mist before the mountain; a heavy curtain of artillery fire. The movable screen or drape in a theater or hall that separates the stage from the auditorium or that serves as a backdrop. The rising or opening of a theater curtain at the beginning of a performance or act. The time at which a theatrical performance begins or is scheduled to begin. The fall or closing of a theater curtain at the end of a performance or act. The concluding line, speech, or scene of a play or act. The part of a rampart or parapet connecting two bastions or gates. Architecture A curtain wall. Slang The end. Slang Absolute ruin: "If the employee doesn't shape up, it's curtains\u201d ( Business Week). Slang Death. To provide (something) with or as if with a curtain. To shut off (something) with or as if with a curtain.