what is a venn diagram 
a venn diagram is an illustration that uses overlapping circles to show the logical relation between two or more sets of items circles that overlap have a commonality while circles that do not overlap do not share those traits the venn diagram was popularized by john venn in the 1880s venn diagrams help to visually represent the similarities and differences between two concepts they have long been recognized for their usefulness as educational tools since the mid 20th century venn diagrams have been used as part of the introductory logic curriculum and in elementary level educational plans around the world understanding venn diagramsvenn diagrams are useful for illustrating how different concepts or factors intersect with one another they can show at a glance how things are similar or different and where and how they overlap often the center of a venn diagram the intersection of two or more circles represents some nexus or main idea that can be decomposed into the various other circles with labels on the outer portions more distinct than those toward the center the overlapping areas can also be used to show where two otherwise disparate contexts share commonalities for instance in the example diagram below we see that while the urban and rural contexts are distinct with their own set of activities they also share sporting events while there are many ways to organize a venn diagram they most often consist of overlapping circles each circle by itself represents a set which may include ideas concepts numbers or objects 