A dictionary is similar to a list, but you access values by looking up a key instead of an index. A key can be any string or number. Dictionaries are enclosed in curly braces, like so:

d = {'key1' : 1, 'key2' : 2, 'key3' : 3}

This is a dictionary called d with three key-value pairs. The key 'key1' points to the value 1, 'key2' to 2, and so on.

Dictionaries are great for things like phone books (pairing a name with a phone number), login pages (pairing an e-mail address with a username), and more!