stimulus

From Wiktionary

Pronunciation[change]

Noun[change]

Singular
stimulus

Plural
stimuli

  1. A stimulus is an event that causes a system to change its output or behavior.
    The primary goal of the $31 billion economic stimulus package was to increase job growth.
  2. (psychology) A stimulus is something that is noticed by the senses.
    The mice responded with fear to the painful stimulus.