Perhaps you mean the Venn diagram.
a Venn diagram consists of two overlapping circles, and is generally used as a compare and contrast diagram. a diagram in general is just a way to show information. in short, they are not the same thing, a venn diagram is a type of diagram.
comparison and contrast
graph
Sankey diagram is named after Irish Captain Matthew Henry Phineas Riall Sankey. He first used this type of diagram in 1898.
pie graph
Venn
gene map
a diagram
diagram
a diagram
a diagram
a diagram
A cladogram is used!
DIAGRAM
DIAGRAM
evolutionary
An energy flow diagram is normally a flow diagram showing the energy gains and energy losses of a given process. This type of diagram is often used to show the efficiency of a given system or lack thereof.