ζωή is the translation of βίος in modern greek , βίος is an ancient greek word that means life , ζωή is a modern greek word that means life . We use ζωή to speak about life but there are a lot of words in modern greek , composite words , that use βίος as first or second synthetic of the word . For example : βιολογία (βίος + λόγος) = biology . Αερόβιος (αέρας + βίος ) someone who live in the air , birds . Also when someone use βιος like monosyllable without a tone on the ι then it means : belongings . For example : Σπατάλησε όλο το βιος του πατέρα του , Means : he wasted all his father's property. In the end i think you only need to know ζωή .