ἐπιβεβαίωσις
From LSJ
κάλλιστον ἐφόδιον τῷ γήρᾳ ἡ παιδεία (Aristotle, quoted by Diogenes Laertius 5.21) → the finest provision for old age is education
English (LSJ)
-εως, ἡ, further confirmation, Id.Rh.Al.1438b29 (pl.); guarantee, Sammelb. 5240.17 (i A.D.).
Greek (Liddell-Scott)
ἐπιβεβαίωσις: -εως, ἡ, ὡς καὶ νῦν, περαιτέρω βεβαίωσις, Ἀριστ. Ρητ. π. Ἀλ. 33, 1.