In 19th century, George Cantor was the first mathematician who gave the concept of set.

1.1 Set

Define set

We often use some words in our daily life that represent a collection of things like dinner set, sofa set, tea set, group of boys, a team of players, a bunch of keys, crowd of people, a cluster of trees, a flock of sheep. The words set, group, team, bunch, crowd, cluster, flock are used to denote collection of things in daily life.

In mathematics collection of things is called set.

In mathematics we describe a set as:

A set is a collection of 'well defined' and 'distinct' objects.

The term 'Well defined' means a set must have some specific property so, that it can easily be identified whether or not an object belongs to the given set.

Whereas the word 'Distinct' means different objects.