ὅ τι
Κάλλιστόν ἐστι κτῆμα παιδεία βροτοῖς → Doctrina hominibus optima est possessio → für Sterbliche ist Bildung das wertvollste Gut
English (LSJ)
or ὅτι (as it is freq. written exc. in 1, sometimes also ὅ, τι), Ep. ὅττι, neut. of ὅστις, used as an A dv. A like διότι, in indirect questions, for what, wherefore, ὅς κ' εἴποι, ὅ τι τόσσον ἐχώσατο Il.1.64, cf. Od.19.464; εἴρετο, ὅ τι οὐ χρᾶται τῇ χειρί Hdt.3.78, cf. 1.111, 2.19,91, al.; ἢν μὴ φράσῃς ὅ τι . . unless you tell me why... Ar.Pl.19, cf. 966: sometimes with a Prep., εἰρωτώμενος κατ' ὅ τι . . οὕτως ἐπέστειλε Hdt.6.3. II ὅ τι μή (usu. written ὅτι μή), after a neg. clause, except, Il.16.227 (v.l. ὅτε μή); οὐδαμοί... ὅ τι μὴ Χῖοι μοῦνοι Hdt.1.18; οὐδεὶς ἀνθρώπων, ὅ τι μὴ γυνὴ μούνη ib.181, cf. 143, Th.4.26, etc.: rarely with a different Verb, διέφυγε μὲν οὐδείς, ὅ τι μὴ διέλαθέ τις no one escaped, save that one escaped notice, Arr.An.1.16.2, etc.: after a question with οὐ, so far as not, οὐ . . τὴν ἀπὸ τοῦ μανθάνειν [ἡδονήν], ὅ τι μὴ μάθημα τιμὴν φέρει, καπνὸν καὶ φλυαρίαν [ἡγεῖται]; Pl.R.581d.—That this phrase belongs to the pronominal ὅ τι is shown by the similar usage of ὅσον, v. ὅσος IV. 5c. 2 so ὅτι ἀλλ' ἤ, = ὅτι μή, LXX 1 Ki.30.17, al. III with a Sup. Adv., ὅττι τάχιστα as quick as possible, Il.4.193, Od.5.112, al.; also ὅ τι τάχος Hdt.9.7.β, S.Ant.1321 codd. (lyr., dub. l.), Th.7.42, etc.; ὅ τι μάλιστα Id.5.36, etc.; ὅ τι ἐγγύτατα Id.3.40; ὅ τι ἐλάχιστα Id.6.23; ὅ τι χρησιμώτατα Id.7.74: also with Adjs., ὅ τι πλείστη ἀπορία Id.4.32; ὅ τι πλεῖστον ναυτικόν, ὅ τι πλεῖστον χρόνον, X.HG4.8.6, Cyr.6.1.43; ὅ τι πλείστη εὐδαιμονία Pl.R.421b; ὅ τι μεγίστη πρόφασις Th.1.126, cf. 7.69; παῖδας ὅ τι χειροτεχνικωτάτους Ar.V.1276, etc.— Here also the usage may be compared with that of ὅσος 1.7, IV.4.