εἰδείην (eideien)
εἰδείην is an Ancient Greek form of οἶδα, meaning “to know”. It is the 1st person singular perfect active optative.
Found 27 times in the Ancient Greek texts on Socratos.
Where it is used
Euripides, Heracles 617: οὐκ οἶδʼ· ἵνʼ ἐλθὼν τἀνθάδʼ εἰδείην πάρος.
All forms of οἶδα (conjugation table)
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.