LSJ
ατος, τό, = πλάτυσμα, plate, π. χρυσοῦν, ἀργυροῦν, BGU 162.3, 7 (ii/iii AD); μολυβοῦν PMagPar. 1.329, cf. PMagLond. 121.438.
flat cake, AB 294, 317.
Liddell-Scott-Jones, Greek-English Lexicon (9th ed., 1940)
Pape
τό, = πλατύσμα, B.A. 294, 317.
Pape, Griechisch-deutsches Handwörterbuch (3. Aufl., 1914)