ἄθος

From Koine Greek ἄνθος (ánthos, “flower”) following Medieval Greek phonotactics where nasals are dropped before fricatives ([nθ] → [θ]).

ἄθος • (áthos) n (genitive ἄθους); third declension (Byzantine)

1. (Byzantine) flower, blossom
2. (Byzantine) (figuratively) an ornament, beautiful object or person
3. (Byzantine) (colloquial) an endearing term of address
4. (Byzantine) (figuratively) a select group of people, cream of the crop
5. (Byzantine) (figuratively) effect or consequence, fruit of one's actions

Probably related to Ionic Greek αἴθω (aíthō, “to ignite”) and Koine Greek αἰθάλη (aithálē, “soot”).

ἄθος • (áthos) n (genitive ἄθους); third declension (Byzantine)

1. (Byzantine) ash, cinder
   • ca 1590–1610, Vitsentzos Kornaros, Erotokritos, Β' 254:

     ...καίγεται, κὶ ἄθος γίνεται, καὶ πάλιν ξανανιώνει

     ...kaígetai, kì áthos gínetai, kaì pálin xananiṓnei

     ...it burns, and it becomes ash, and again it is revitalised

ἄθος - Kriaras, Emmanuel (vol.1 1969-) Επιτομή του Λεξικού της Μεσαιωνικής Ελληνικής Δημώδους Γραμματείας (Epitomí tou Lexikoú tis Mesaionikís Ellinikís Dimódous Grammateías) [Concise Dictionary of Medieval Vulgar Greek Literature (1100–1669) Vols. I–XIV] (in Greek) Online edition (22 vols. printed edition)