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.]
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