limen

{{short description|Threshold of perception or response}}

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In physiology, psychology, or psychophysics, a limen or a liminal point is a sensory threshold of a physiological or psychological response. Such points delineate boundaries of perception; that is, a limen defines a sensory threshold beyond which a particular stimulus becomes perceivable, and below which it remains unperceivable.{{cite journal|first1=Jameson K. |last1=Holden|first2= Eric M. |last2=Francisco|first3= Zheng |last3=Zhang|first4=Cristina |last4=Baric|first5= Mark |last5=Tommerdahl|title=An Undergraduate Laboratory Exercise to Study Weber's Law|journal=Journal of Undergraduate Neuroscience Education|volume=9|issue=2|pages=71–74|date=2011|pmid=23493843 |pmc=3592720}}

Liminal, as an adjective, means situated at a sensory threshold, hence barely perceptible. Subliminal means below perception.

The absolute threshold is the lowest amount of sensation detectable by a sense organ.