Sense

1. (relative pronoun) such as; what sort, manner, kind of
2. (in an independent sentence serves as an exclamation and expresses astonishment at something unusual)
3. (also in indirect sentences, where no antecedent can be supplied)

Examples

• εἶπε δὲ αὐτοῖσ Ἰωσήφ. τί τὸ πρᾶγμα τοῦτο ἐποιήσατε̣ οὐκ οἴδατε ὅτι οἰωνισμῷ οἰωνιεῖται ὁ ἄνθρωποσ, οἷοσ ἐγώ̣ (Septuagint, Liber Genesis 44:15)
• καὶ πάλιν ἐλεήσει αὐτοὺσ ὁ Θεὸσ καὶ ἐπιστρέψει αὐτοὺσ εἰσ τὴν γῆν, καὶ οἰκοδομήσουσι τὸν οἶκον, οὐχ οἷοσ ὁ πρότεροσ, ἕωσ πληρωθῶσι καιροὶ τοῦ αἰῶνοσ. καὶ μετὰ ταῦτα ἐπιστρέψουσιν ἐκ τῶν αἰχμαλωσιῶν καί οἰκοδομήσουσιν Ἱερουσαλὴμ ἐντίμωσ, καὶ ὁ οἶκοσ τοῦ Θεοῦ ἐν αὐτῇ οἰκοδομηθήσεται εἰσ πάσασ τὰσ γενεὰσ τοῦ αἰῶνοσ οἰκοδομῇ ἐνδόξῳ, καθὼσ ἐλάλησαν περὶ αὐτῆσ οἱ προφῆται. (Septuagint, Liber Thobis 14:5)
• Οὐδὲ εἷσ ἐκτίσθη οἷοσ Ἐνὼχ τοιοῦτοσ ἐπὶ τῆσ γῆσ. καὶ γὰρ αὐτὸσ ἀνελήφθη ἀπὸ τῆσ γῆσ. (Septuagint, Liber Sirach 49:14)
• ἔτι δὲ τοιοῦτόσ ἐστιν ὁ μικρόψυχοσ οἱο͂σ πάντα τὰ ὀλιγωρήματα καλεῖν ὕβριν καὶ ἀτιμίαν, καὶ τὰ δι’ ἄγνοιαν ἢ λήθην γιγνόμενα. (Aristotle, Virtues and Vices 42:3)
• ταῦτα μὲν καὶ τὰ τοιαῦτα πολλὰ ἕτερα εἴποι τισ ἂν οἱο͂σ σὺ κατηγορῶν ἐν οὕτωσ ἀμφιλαφεῖ τῇ ὑποθέσει καὶ μυρίασ τὰσ ἀφορμὰσ παρεχομένῃ· (Lucian, Apologia 19:1)

Source: Ancient Greek entries from Wiktionary