A map or dictionary represents an association which maps elements, called keys, to other elements, called values, such that for each one key, there is exactly one value.
Each key-value pair is called a Map Entry.
For example, an association which linked "Mark" with the amount "10 dollar", "Alice" with "5 dollar" and "Charlie" with "10 dollar" would be a map with three entries, with keys "Mark", "Alice" and "Charlie" and values "10 dollar", "5 dollar" and "10 dollar", respectively.
A map can have no entries. To represent that, use "(map)"