How does [] work in a function in Clojure?

```
(def square (fn [x] (* x x)))
(square 10) ; -> 100

```

As I understand from the above, we pass 10 in the place of x. Shouldn't I be able to do the following?

```
(def square (fn [x y] (* x y)))
(square 5 10) ; -> 50

```