The answer to the crossword puzzle is 'OVERLAP'. What circles in a Venn diagram do is OVERLAP with each other. A Venn diagram is a visual representation of the relationships between different sets of data. It consists of two or more circles that represent the different sets of data and the area where they OVERLAP represents the shared elements between them. The overlapping circles in a Venn diagram are used to illustrate the similarities and differences between the different sets of data.