πετρίδιον
From LSJ
τῶν δ᾽ ὀρθουμένων σῴζει τὰ πολλὰ σώμαθ᾽ ἡ πειθαρχία → But of those who make it through, following orders is what saves most of their lives (Sophocles, Antigone 675f.)
English (LSJ)
τό, Dim. of πέτρα, Arist.HA547b21, Fr.338, Thphr.Fr.160, AP9.570 (Phld.), Porph.Abst.2.17.
German (Pape)
[Seite 606] τό, dim. von πέτρα, kleiner Fels; Arist. H. A. 5, 15; Ath. VII, 323 d.
Greek (Liddell-Scott)
πετρίδιον: τό, ὑποκορ. τοῦ πέτρα, Ἀριστ. π. τὰ Ζ. Ἱστ. 5. 15, 16, Ἀνθ. Π. 9. 570, Ἀθήν. 323D, κτλ.