n. pl. im·pe·tus·es
1. An impelling force; an impulse.
2. The force or energy associated with a moving body.
a. Something that incites; a stimulus.
b. Increased activity in response to a stimulus: The approaching deadline gave impetus to the investigation.
[Middle English impetous, from Latin impetus, from impetere, to attack : in-, against; see in-2 + petere, to go towards, seek; see pet- in Indo-European roots.]
CITE: American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.