[racket] the definition of 'form'?

Where would I find out, preferably in the Racket documentation,
the definition of what a 'form' is?  I'm thinking along these lines:

  A form is one of:
    - a symbol
    - a numeric literal
    - a string literal
    - ... possibly other literals? ...
    - a sequence of forms wrapped in one pair of parentheses

Is this the right idea?  Or is the word 'form' reserved only for
things wrapped in parentheses?


Norman


P.S. In the Racket documentation, I found the section on 'Syntactic
Forms', but I haven't found a definition of what a form is, and I
haven't found the word 'form' in the index.