Dictionary. A dictionary is a list of associations between a key and an object. Of course a key is an object, but it must respond to equality tests. Most of the time, symbols are used as keys.
I don't think that -> was introduced before as a shorthand for associationts, tuples, cons pairs. For example:
Smalltalk
Association key: #red value: Color red
can be rewritten as:
```Smalltalk
red -> Color red
```