LSJ
εως, ἡ, mixing, mingling, μ. τε διάλλαξίς τε μιγέντων Emp. 8.3, cf. Pl. Phlb. 47d, al., Arist. GA 327a30, etc. ; τινὶ πρός τι Pl. Sph. 260b; πάσας μ. μείγνυσθαι Id. R. 620d.
intercourse with others, esp.
sexual intercourse or commerce, Hdt. 1.203, al. ; [γυναικῶν] ἐπίκοινον τὴν μ. ποιεῖσθαι Id. 4.172; ὄνων πρὸς ἵππους Anacr. 35; ἄρρενος πρὸς ἄρρεν, θήλεος πρὸς θῆλυ μ. Plu. 2.990d; ἡ τῶν παίδων μ.
union for the sake of…, Pl. Lg. 773d. (In codd. sts. μῖξις, for which μεῖξις shd. prob. be restd. in Prose; — with μεῖξις ; μίξις, cf. φεῦξις ; φύξις.)
Liddell-Scott-Jones, Greek-English Lexicon (9th ed., 1940)