1. A small grain or pellet; a particle.
2. Geology A rock or mineral fragment larger than a sand grain and smaller than a pebble, between 2 and 4 millimeters in diameter.
3. Astronomy One of the small, transient, luminous markings in the photosphere of the sun.
4. Biology A cellular or cytoplasmic particle, especially one that stains readily.
[Late Latin grānulum, diminutive of Latin grānum, grain; see gə-no- in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 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.