A Venn diagram is a visual tool used to show the relationships between different sets. It typically consists of overlapping circles, where each circle represents a set. The areas where the circles overlap indicate common elements shared between the sets, while the non-overlapping areas show elements unique to each set. Venn diagrams are often used in mathematics, logic, and statistics to illustrate concepts such as union, intersection, and difference. They can also be applied in various fields, including education and business, to compare and contrast different ideas or groups effectively.