I is for Impresario and for Interval but again there aren’t that many terms so here goes with what we have. A funny feeling says that next time with J is also going to be a bit sparse…

IMPRESARIO - A producer, especially of musical entertainments. 

IMPROVISATION or IMPROV - A spontaneous form of theatre that is inspired by the audience and so is never the same show twice and all produced on the spot.

IN THE ROUND - A stage setup in which the audience is seated completely around the playing area, as in an arena stage. 

INDUCTION LOOP - System which amplifies audio frequency currents (from a microphone over the stage) around a large loop of cable (around the auditorium) to generate a magnetic field which can be picked up by a hearing aid switched to the "T" position. 

INFLECTION - The variation in the pitch of an actor's voice as he reveals emotion. 

INSET  - A small scene set inside a larger one. 

INTENSITY - Degree of purity or saturation of colour. Brightness of light from any given piece of equipment in any given area.

INTERMISSION or INTERVAL - A period between acts, when the houselights are brought up and the au=dience and the actors get a break for a few minutes. Time for Ice creams or a quick drink at the bar.

IRIS - An adjustable assembly of flat, overlapping leaves in a frame mounted at or near the internal focal point of the lens-lamp reflector system of a spotlight to provide control of the area illuminated.