ὑπομάζιον
From LSJ
Ἃ δέ σοι συνεχῶς παρήγγελλον, ταῦτα καὶ πρᾶττε καὶ μελέτα, στοιχεῖα τοῦ καλῶς ζῆν ταῦτ' εἶναι διαλαμβάνων (Epicurus, Letter to Menoeceus 123.2) → Carry on and practice the things I incessantly used to urge you to do, realizing that they are the essentials of a good life.
Russian (Dvoretsky)
ὑπομάζιον: τό (sc. τέκνον) грудной младенец Diod.