A collection of "things" (objects or numbers, etc).

Each member is called an element of the set.

There should be only one of each member (all members are unique).

Here is a set of clothing items.

Another Example: {1,2,3,4} is the set of counting numbers less than 5

Each member is called an element of the set.

There should be only one of each member (all members are unique).

Here is a set of clothing items.

Another Example: {1,2,3,4} is the set of counting numbers less than 5