The component or characteristic of an external stimulus which initiates a particular innate behavioural response in an animal perceiving it, regardless of the presence or absence of the remainder of the stimulus.
Origin
1930s.
Definition of sign stimulus in US English:
sign stimulus
noun
Zoology
The component or characteristic of an external stimulus which initiates a particular innate behavioural response in an animal perceiving it, regardless of the presence or absence of the remainder of the stimulus.