1. A group of the same or similar elements gathered or occurring closely together; a bunch: "She held out her hand, a small tight cluster of fingers" (Anne Tyler).
2. Linguistics Two or more successive consonants in a word, as cl and st in the word cluster.
3. A group of academic courses in a related area.
v. clus·tered, clus·ter·ing, clus·ters
To gather or grow into bunches.
To cause to grow or form into bunches.
[Middle English, from Old English clyster.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.