ἐρυθρός
erythrós
“red”
4 words in English grow from this root.
Erysipelas
Medicineἐρυθρόςerythrós
“red skin”
Erythema
Medicineἐρυθρόςerythrós
“a reddening”
Erythrocyte
Medicineἐρυθρόςerythrós
“red hollow vessel”
Erythropoietin
Medicineἐρυθρόςerythrós
“red-maker”