theatrical world; the stage
Refers to the world of theater as a professional or artistic community, not a physical stage. Often used in contexts like 劇壇にデビューする (make one's debut on the stage/in the theater world).
彼は若くして劇壇にデビューした。
He made his debut on the stage at a young age.
彼女は劇壇で高い評
She is highly regarded in the theatrical world.
Compound of 劇 (drama, play) and 壇 (platform, stage). The combination refers to the theatrical world or stage as a professional sphere.