Apron – The area of a stage, if any, that extends beyond the proscenium arch
Auditorium – The main area where audience members are located during a performance
Backcloth – A scenic or plain cloth hung from the back of the set
Beginners – The call made prior to curtain up for cast on stage at the start of the performance to get into position on stage. The call is often made 5 minutes before curtain up
Blackout – During a blackout stage lights are switched off
Blocking – Planning and setting out the movements of cast who are on stage
Blueout – Similar to a blackout but some stage lights are left on (often set to a dim blue) so that there is sufficient light for scene changes
Bookflat – Two (or in some cases more) flats that are hinged together
Border – Cloth masking that is hung above the stage to hide lighting fixtures and other accessories
Box Set – A set with three enclosed sides
Brace – Metal or wood supports for a flat
Call / Caller – The person responsible for telling the cast to take their positions during the performance
Cloth – A piece of material, which is often painted and can form part of the scenery
Crossfade – The change from one lighting or sound scene to another without a blackout or silence