What are cues?

The manual says:
  
A cue is a record target comprised of channels with associated parameter data, discrete (channel/parameter level) timing, cue timing, and cue attributes (such as preheat, follow or hang instructions).

I think of a cue as an instruction to do something. Something might include:

• set the intensity of some fixtures to a new value with timing
• run a macro
• send an OSC command to another system
  

www.youtube.com/watch

It's one lighting state ("look") including the speed how to get there. Cues live in a cue list, so cues have a determined order. Other than e.g. presets or subs that can also contain a whole look, but unlike cues those don't have a determined before and after