Sense

1. who or which at least
2. quippe qui, since it was they who

Examples

• Αἰᾶ́ γε μὴν ἔτι νῦν μένει ἔμπεδον υἱωνοί τε τῶνδ’ ἀνδρῶν, οὓσ ὅσγε καθίσσατο ναιέμεν Αἰᾶν, οἳ δή τοι γραπτῦσ πατέρων ἕθεν εἰρύονται, κύρβιασ, οἷσ ἔνι πᾶσαι ὁδοὶ καὶ πείρατ’ ἐάσιν ὑγρῆσ τε τραφερῆσ τε πέριξ ἐπινισσομένοισιν. (Apollodorus, Argonautica, book 4 5:22)

Source: Henry George Liddell. Robert Scott. "A Greek-English Lexicon". revised and augmented throughout by. Sir Henry Stuart Jones.