LSJ
Ion. θρομβήϊον, τό, Dim. of θρόμβος, Nic. Al. 295; — also θρομβίον, τό, Dsc. Alex. 25.
Liddell-Scott-Jones, Greek-English Lexicon (9th ed., 1940)
Pape
τό, ion. θρομβήϊον, dim. von θρόμβος, Klümpchen, Nic. Al. 295.
Pape, Griechisch-deutsches Handwörterbuch (3. Aufl., 1914)