GRC
Bailly
ωνος (ὁ) = lat. săpo, ōnis, savon, ARÉT. Cur. m. diut. 2, 13 (mot celtique ou germain, sel. PLIN. H.N. 28, 12).
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LSJ
ωνος, ὁ, Lat. sapo, soap, τῷ Γερμανικῷ σμήγματι (καλεῖται δὲ σ.) Ruf. ap. Orib. 45.29.59, cf. Asclep. ap. Gal. 12.586, Aret. CD 2.13; — a Gallic invention (hair-dye) adopted by the Germans acc. to Plin. HN 28.191. [α, Seren. Sammon. 153.] (The Germanic forms (OHG. seifa, OE. sápe, etc.) come fr. prim. Germanic *saipjō, whence also Finn. saippio; cf. σήπων.)
Liddell-Scott-Jones, Greek-English Lexicon (9th ed., 1940)
Pape
ωνος, ὁ, Seife, lat. sapo, keltisches od. deutsches Wort. Sp.
Pape, Griechisch-deutsches Handwörterbuch (3. Aufl., 1914)