Clustering can refer to

• Computer clustering - the connection of many low-cost computers to be used as one larger computer.

• In computer science, the undesirable, contiguous grouping of elements in a hash table.

• Data clustering - a technique for data analysis by partitioning a data set into subsets whose elements share common traits.

• In demographics, the gathering of various populations based on ethnicity, economics or religion.

• In writing, a "pre-writing" technique to organize ideas using "ball-and-stick" diagrams similar to mind maps. The term was popularized by Gabriele Rico's 1983 book Writing the Natural Way: Turn the Task of Writing Into the Joy of Writing.