Also spelled infra-red
Freq #12868
Meanings
- 1
- 2
Thesaurus
Synonyms
2
noun
· the region or radiation of...
infrared radiationinfrared light
Word family
Derived forms
midinfrarednoninfrared
Appears in
Etymology
From infra- (Latin for "below") + red, because its frequencies lie below those of visible red light. The term replaced the earlier expression calorific rays in the nineteenth century.