Here are some examples:
* The students clustered around the professor after class.
* The grapes clustered tightly on the vine.
* The data points clustered in a specific area of the graph.
It can also mean to form or arrange into a cluster:
* The artist clustered the flowers in a vase.
* The company clustered its offices in a central location.
The word "cluster" can also be used in a more figurative sense, meaning to concentrate or focus:
* The media clustered around the celebrity.
* The attention clustered on the new product.