• Solo light entertainment singers
• Pop singers and pop groups
• Stunt or fight arrangers
• Stunt performers
• Choreographers
• Chorus singers (including the lay clerks of Westminster Abbey, Westminster Cathedral and St Paul’s Cathedral, but not choristers there or elsewhere, or lay clerks and choristers in other cathedrals or churches of similar status, who are represented by the Incorporated Society of Musicians)
• Supporting artists (crowd) and walk-ons (individual characterisation).

Some of these definitions are a bit arcane and convoluted. Where the application of this agreement ends and that of the BBC’s agreement with the Musicians’ Union begins can occasionally be unclear. For example, while Equity terms apply to the

engagement of "pop groups", MU terms apply to that of "jazz groups". And the dividing line between the different sections of the BBC/Equity agreement can be controversial, too: puppeteers, for example, are included in the section governing actors, rather than that dealing with variety acts.

But of course the descriptive terms applied to the different kinds of people who make a living from appearing on the stage and on television are just that: descriptive, not definitive; and people of that kind are constantly inventing new ways of using the stage and television in the pursuit of art and/or entertainment. These definitions are an attempt — and in the vast majority of cases a successful attempt — to define things that are constantly changing.