An array is a fixed length collection of data elements all of the same type.
The data type for an array is [T;N] where T is the elements' type, and N is the fixed length known at compile-time.
Individual elements can be retrieved with the [x] operator where x is a usize index (starting at 0) of the element you want.
Collections with a dynamic length, often called dynamic or variable arrays, are introduced in a later chapter about Vectors.