ἐφʼ (eph)
ἐφʼ is an Ancient Greek form of ἐπί, meaning “on, upon, at, against, toward (+gen./dat./acc.)”. It is the preposition.
Found 4,884 times in the Ancient Greek texts on Socratos.
Where it is used
Apollonius Rhodius, Argonautica 1.36: γείνατο δινήεντος ἐφʼ ὕδασιν Ἀπιδανοῖο,
Thucydides, History of the Peloponnesian War 1.4.1: … ᾶρας ἐξελάσας καὶ τοὺς ἑαυτοῦ παῖδας ἡγεμόνας ἐγκαταστήσας· τό τε λῃστικόν, ὡς εἰκός, καθῄρει ἐκ τῆς θαλάσσης ἐφ’ ὅσον ἐδύνατο, τοῦ τὰς προσόδους μᾶλλον ἰέναι αὐτῷ.
Plutarch, Numa 7.5: … ς τινὰς ὄντας, ὡς ἱστοροῦσι, τῶν Ἑλληνικῶν ὀνομάτων τότε μᾶλλον ἢ νῦν τοῖς Λατίνοις ἀνακεκραμένων. καὶ γάρ ἃς ἐφ ό ρουν οἱ ἱερεῖς λαίνας ὁ Ἰόβας χλαίνας φησὶν εἶναι, καὶ τὸν ὑπηρετοῦντα τῷ ἱερεῖ τοῦ Διὸς ἀμφιθαλῆ παῖδα λέγ …
Source: Socratos (socratos.org), a free reader for Ancient Greek and Latin. Grammar from the Perseus Treebank and Morpheus; dictionary entries from Liddell-Scott-Jones, A Greek-English Lexicon (Perseus Digital Library, CC BY-SA). Counts are from the texts on Socratos.