> Hello,
> Why is the length of (quote '(1 2 3)) 2 not 3?
> For example:
> CG-USER(3): (length (quote '(1 2 3)))
> 2

It has nothing to do with LENGTH.

The argument provided to LENGTH in your example is the value of the
expression (QUOTE '(1 2 3)).

Its value is '(1 2 3).

'(1 2 3) is an abbreviation for (QUOTE (1 2 3)),
which is a TWO-element list consisting of the symbol QUOTE
and the three-element list (1 2 3).

 -Bob