Take a look at Dictionary.class.st for example https://github.com/pharo-project/pharo/blob/bc8b9658958f4464189cf3e7fffd8c9bf775f85f/src/Collections-Unordered/Dictionary.class.st
on line 10: I am use when we need a collection of objects which I can access with a key. For example if you associate some words with a definition, the word will be the key and the definition will be the value. Both of them can be any kind of objects. At each commit, the number of odd characters increases...
