[racket] object-language in redex/tutorial.html

What does "object-language" mean in 
http://docs.racket-lang.org/redex/tutorial.html ?

It pops up first here:

"Once we have defined the grammar, we can ask Redex if specific terms 
match the grammar. This expression checks to see if the e non-terminal 
(from L) matches the object-language expression (λ (x) x)."

That term isn't in the defined language L (no type), so the match fails. 
Then object-language pops up again in Exercise 1:

"Use redex-match to extract the body of the function from this 
object-language program:

((λ (x) (+ x 1))
    17)"

Is object-language a predefined language? Or does the exercise expect me 
to use define-language to create an appropriate object-language without 
types?

-- 
Anthony Carrico