1. The use of physical or mental energy to do something; exertion.
2. A difficult exertion of strength or will: It was an effort to get up.
3. A usually earnest attempt: Make an effort to arrive promptly.
4. Something done or produced through exertion; an achievement: a play that was his finest effort.
a. Force applied against inertia.
b. The force needed by a machine to accomplish work on a load.
[Middle English, from Old French esfort, from esforcier, to force, exert, from Medieval Latin exfortiāre : Latin ex-, ex- + Latin fortis, strong; see bhergh-2 in the Appendix of Indo-European roots.]
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.