Infrared is the band of radiation just beyond red light, felt as heat. Infrared camera, infrared radiation, an infrared remote.
Every warm object gives it off, which is why a thermal camera can see people in the dark. Remote controls use it, which is why one must be pointed at the television and will not work through a wall.
1nouninfraredThe band of radiation just beyond red light, felt as heat.
“Night-vision cameras use infrared to see in the dark.”
infrared is a radiation.
Infra-, below, plus red, since the band lies below red in frequency.
Middle English
red
English
red
English, today
infrared
From infra + red. red comes from Middle English red. 2 See also West Frisian read, Low German root, rood, rot, rod, Dutch rood, German rot, Danish and Norwegian Bokmål rød, Norwegian Nynorsk raud, Swedish röd, Faroese reyður, Icelandic rauður; also Welsh rhudd, Latin ruber, rufus, xto rtär, txb ratre, Ancient Greek ἐρυθρός, Albanian pruth (“redhead”), Russian ру́дый (rúdyj) ("red", "redhaired"). Czech rudý, Lithuanian raúdas, Finnish rauta, Estonian raud, Serbo-Croatian riđ ("reddish", "red"), ae 𐬭𐬀𐬊𐬌𐬛𐬌𐬙𐬀, Sanskrit रुधिर (“red, bloody”).
Etymology from Wiktionary, CC BY-SA