Degree of advancement in the histrionic art (5)

I believe the answer is:

stage

I'm a little stuck... Click here to teach me more about this clue!

'degree' is the definition.
(I know that degree can be written as stage)

I can't explain the remainder of the clue.

(Other definitions for stage that I've seen before include "Theatre platform; leg" , "Mount (a play)" , "Elevated platform" , "Section (of journey)" , "Support for acting" .)

I've seen this clue in the Evening Standard.

Want a hint initially instead of a full solution? Install my app