1. The act or process of adding; addition.
2. A sum or aggregate.
3. A concluding argument after the presentation of a legal case, especially an argument made to a judge or jury by an attorney for a party as to why that party should prevail.
4. Physiology The process by which multiple or repeated stimuli can produce a response in a nerve, muscle, or other part that one stimulus alone cannot produce.
[New Latin summātiō, summātiōn-, from Late Latin summātus, past participle of summāre, to sum up, from Latin summa, sum; see SUM.]
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.