A theatrical cue is the trigger for an action to be carried out at a specific time. It is generally associated with theatre and the film industry. They can be necessary for a lighting change or effect, a sound effect, or some sort of stage or set movement/change.
We should note here that actors will also take cues from each other, lighing and sound effects or any other source.
Cue sheets contain all the important data about cues fro the show. The Stage manager will ideally have a global cue sheet detailing lighting, sound, video and any other cues. Each other team LX or Sound for example would have their own. Cue are often assigned visually on the script and also in a cue sheet and different areas have a different notation.
Lighting – LX
Sound – SX
Video- VX
I found this document Marking Cues and simple and easy document to start with
We have been using Qlab which is a computer based cue system. This can control many aspects of the performance at the press of a button.
some example cue sheets can be found here
https://www.filmsourcing.com/download-free-cue-sheet-template/
https://drive.google.com/file/d/0B1xtyxCBxwkCNjlZbklycngxbms/view
http://www.langhamtheatre.ca/wp-content/uploads/2012/02/stagemanagerhb.pdf
Another term for this can be a plot sheet – this is often a live working version which the controlling person has to make notes and amendments on as necessary.
http://www.theatrecrafts.com/pages/home/topics/lighting/lighting-design-paperwork/
Matt Cooper 