a. The act or process of expanding: the new nation's expansion westward.
b. The state of being expanded.
a. An expanded part: an expansion of a river.
b. A product of expanding: a book that is an expansion of the author's PhD thesis.
3. The extent or amount by which something has expanded.
a. A quantity written in an extended form, such as in a sum or product of terms.
b. The process of obtaining this form.
5. An expanse.
6. A period of increased economic or business activity.
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.