Dictionary represent the collection of elements in the form of key - value pair.Dictionary is an unordered set of key and value pair. It is a container that contains data, enclosed within curly braces.
Dictionaries are indexed by keys, which can be any immutable type; strings and numbers can always be keys.
Tuples can be used as keys if they contain only strings, numbers, or tuples; if a tuple contains any mutable object either directly or indirectly, it cannot be used as a key.
Keys of Dictionary must be unique.