# What does $\to$ mean in the following definition of a block cipher?

In the following picture $\kappa$ is the key length and $n$ is the block size.

I understand that $\{0,1\}^\kappa$ means all possible combination of keys and $\{0,1\}^n$ means all possible combination of a plain-text block.

But I don't understand the overall equation, specially the meaning of the arrow $\to$. Can anyone explain it in brief? (note: I am very weak in mathematics)

Let $E: \{0,1\}^\kappa \times \{0,1\}^n \to \{0,1\}^n$ be a block cipher with a $\kappa$ bit key and an $n$-bit state.

That definition is a standard definition which defines encryption as a function $E$. That function takes two inputs, a $\kappa$ bit key and a $n$ bit message. Hence it is defined over the cartesian product - denoted as $\times$ - over these two sets, i.e. all bitstring of length $\kappa$ and $n$ respectively. It maps - denoted as $\rightarrow$ - to an $n$ bit output (the ciphertext).