I am using Office Excel 2003. According to the offline Help page, the
second argument of RANK() is (emphasis added): "an __array__ of, or a
reference to, a list of numbers". So why does the following result in
a syntax error?

=rank(1, {2,1})

Isn't {2,1} "an array of" a list of numbers?

Obviously, I can work around this by putting 2 and 1 into B1:B2, for
example, and using =RANK(1,B1:B2). But that is "a reference to" a
list of numbers.