**well-defined sets**

A well defined-set means the element is a member of the set or not.

**Example**

A = {1,3,5,7}

This set is consist of the first four odd numbers. That is a well-defined set.

X = {Biryani, Custered}

This set is consist of two distinct dishes. This is a well-defined set.

**Not well-Defined**

If the element of a set is not well defined then it is called undefined set.