a grouping of a number of similar things
"a bunch of trees"
"a cluster of admirers"
The action of the verb to cluster.
"The bees were clustering on the hive entrance as evening approached."
In plain English: Clustering is when similar things group together naturally because they are alike.
"The clustering of students in the corner made conversation difficult for others to hear."
present participle of cluster
"The birds were clustering together on the branch to keep warm."
In plain English: Clustering means grouping similar things together so they stay close to each other.
"Students were clustering in small groups near the school entrance to discuss their homework."
Forming a cluster.
"The new coffee shops in downtown have been clustering around the central square."