% Glossary

In this section we briefly explain terms that you may not be familiar with.

This book avoids, as much as possible, overcomplicated terms. Nevertheless, the following were deemed important enough that omitting them would be a disservice to the reader.

### Arity

Arity refers to the number of arguments a function or operation takes.

```rust
let x = (2, 3);
let y = (4, 6);
let z = (8, 2, 6);
```

In the example above `x` and `y` have arity 2. `z` has arity 3.