A proscenium theatre should not be confused with a "proscenium arch theatre".

Recent entries about theatre buildings and theatre spaces in books, on various theatre websites, and on Wikipedia, have confused students and learners about the word "proscenium" and the term "proscenium arch". The two terms have very different meanings.

A theatre with a "proscenium" does not have a "proscenium arch" (as the entry below about Classical Theatres and Roman Theatres makes clear).

The word "proscenium" appears on the stage front area Aarend van Buchel's copy of de Witt's drawing showing the interior of the Swan Theatre in Southwark, on the south side of the Thames c.1596. The action of plays performed there (as indicated by actors on its stage front or "proscenium" as it is labelled by Buchel) took place in the midst of the audience, who surrounded the stage on three sides.

It is therefore wrong to regard a "proscenium stage" or a "proscenium theatre" as one where spectators watch the play from the front. They don't: they watch performers from three sides of the stage, and performers act plays in their midst.