A cluster is defined as "a small, close group." Word Clusters are groups of words sharing the same global concept. For example, house, cabin, mansion, and shack are similar in that they are all forms of shelter. However, there are distinct differences that must be distinguished by students to facilitate understanding of the impact of their words in various contexts.
Higginson, B., & Phelan, P. (1986). Word Cluster: A Strategy for Synonym Development. Reading Horizons, 26 (3). Retrieved from http://scholarworks.wmich.edu/reading_horizons/vol26/iss3/4