Any of a range of colours having the longest wavelengths, 670 nm, of the visible spectrum; a primary additive colour for transmitted light: the colour obtained by subtracting green and blue from white light using magenta and yellow filters; the colour of blood, ripe strawberries, etc.
From Middle English red, from Old English rēad, from Proto-West Germanic *raud, from Proto-Germanic *raudaz (compare West Frisian read, Low German root, rod, Dutch rood, German rot, Danish and Norwegian Bokmål rød, Norwegian Nynorsk raud), from Proto-Indo-European *h₁rowdʰós, from the root *h₁rewdʰ- (compare Welsh rhudd, Latin ruber, rufus, Tocharian A rtär, Tocharian B ratre, Ancient Greek ἐρυθρός, Albanian pruth ("redhead"), Old Church Slavonic рудъ, Czech rudý, Lithuanian raúdas, Avestan 𐬭𐬀𐬊𐬌𐬛𐬌𐬙𐬀, Sanskrit रुधिर ("red, bloody")).