# Venn Diagram

## DEFINITION of 'Venn Diagram'

A Venn diagram is an illustration that utilizes circles, either overlapping or non-overlapping, to depict a relationship between finite groups of things. This diagram was named after John Venn, an English philosopher and logician, in 1880.

The basic structure of the Venn diagram is typically overlapping circles, with items in the overlapping section bearing a commonality. Items residing in the outer portions of the circles do not share specified common traits.

## BREAKING DOWN 'Venn Diagram'

Venn diagrams have long been recognized for their usefulness on an educational level. Since the mid-20th century, these diagrams have been used as part of the introductory logic curriculum and in elementary-level educational plans around the world.

## The History of the Venn Diagram

The English logician John Venn invented the diagram in 1880; however Venn originally called the illustration Eulerian circles. American academic philosopher, and the eventual founder of conceptual pragmatism, Clarence Lewis referred to the circular depiction as the Venn diagram in his book "A Survey of Symbolic Logic" in 1918.

Venn studied and taught logic and probability theory at Cambridge University. This is where Venn developed his method of utilizing diagrams to illustrate set theory. Venn published a prolific, precedent-setting work "The Logic of Chance," a book that put forth the frequency theory of probability. Venn touted that probability should be established based on the regularity that something is predicted to occur, contrary to popular educated assumptions. Venn also developed and more fully realized mathematician George Boole’s theories in his book "Symbolic Logic" in 1881. This book was also the work in which Venn highlighted what would eventually become the Venn diagram.