infrared

noun

1. (uncountable)The electromagnetic radiation of a wavelength longer than visible light, but shorter than microwave radiation, having a wavelength between 700 nm and 1 mm.

   “Collisions of these 'transparent' molecules with the molecules that do have absorption bands in the infrared can have a considerable influence on the intensities of the observed absorption bands.”

2. (countable)A specific wavelength in this range.

   “Sonne has shown that by means of the luminous rays the temperature in the tissue may be raised to a higher degree than by the use of the infrareds.”

   “Exposure of spectral pieces at centimeters, millimeters, and infrareds, which provide a top steadiness of the dependence "MCW radiation vs. parameter Δt" and its interannual (seasonal) dynamics.”

3. (countable)A device that emits infrared radiation.

   “In his room, he could install his infrareds without being discovered.”

   “Beams are the active counterparts of passive infrareds (PIRs). Since these are active infrareds, they require two parts: a transmitter and a receiver.”

   “Additionally, infrareds tend to cook food faster so there's less time to render said fat.”

adj

1. (not-comparable)Having a wavelength in the infrared spectrum.
2. (figuratively, not-comparable)Relating to very low energies or very large distances or time spans.

   “Unless otherwise stated, we will be working in Euclidean space compactified to a sphere in order to avoid infrared problems.”

   “Secondly, as stated already by Osborne & Provenzale, pure k^(-α)-behaviour is impossible since there would have to be infinite power at zero frequency (this would correspond to an infrared catastrophe).”

   “Although infrared divergences are of long-distance nature, they often play an essential role in the verification of the validity of the perturbative treatment of short-distance phenomena.”