Look up a name, keep one of each
A map can connect a product code to its price. Give it the code and it finds the matching price, much like looking up a word in a dictionary. The code is the key, and the price is the value.
A set stores items without duplicates. A shop could use one to track which product codes appear in a basket. The order of items is usually less important than quickly checking whether an item is present.
Some programming languages call a map a dictionary. An object can also hold named values, but it may represent a particular thing and include actions. The exact terms and behaviour vary by language.