Etymology

From Sanskrit रुधिर ‎(rudhirá) +‎ -ము ‎(-mu); from Proto-Indo-European *h₁rudʰros ‎(“red”), from the root *h₁rewdʰ- . Cognates include Avestan 𐬭𐬀𐬊𐬌𐬜𐬌𐬙𐬀 ‎(raoiδita-), Ancient Greek ἐρυθρός ‎(eruthrós), Latin ruber, Tocharian A/B rtär/ratre, Old Church Slavonic рудъ ‎(rudŭ), Lithuanian raúdas, and Old English rēad (English red).