A noun, such as furniture, water, or honesty, that cannot be modified by the indefinite article, does not occur in the plural, and is often preceded by modifiers such as some or much or by a phrase containing a unit of measurement. Some nouns can function both as mass nouns (There are sixty boxes of tile in the warehouse) and as count nouns (We had to cut a tile in half to fit the end of the row). Also called noncount noun. See Usage Note at collective noun.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 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.