noun

• (biology) The ability of an organism or organ to respond to external stimuli.
  "The single-imaging optic of the mammalian eye offers some distinct visual advantages. Such lenses can take in photons from a wide range of angles, increasing light sensitivity. They also have high spatial resolution, resolving incoming images in minute detail."
• (biology) The ability of an organism or organ to respond to external stimuli.
• (statistics) The probability, in a binary classification test, of a true positive being correctly identified.
  "Coordinate term: specificity"
• (electronics) The degree of response of an instrument to a change in an input signal.
  "Up to 1,884 microplastic particles were found per cubic metre of seawater in some locations, up to 18 times higher than in similar tests during the last Ocean Race, which ended in 2018. Scientists noted that the sensitivity of their instruments is now higher."