οἶδα to know, εὖ οἶδα I know well; εὖ ἴσθι be assured: often c. acc. rei, νοήματα οἶδε, μήδεα οἶδε he is versed in counsels, Hom.; with neut. Adjs., πεπνυμένα, φίλα, ἀθεμίστια εἰδώς Hom.; also c. gen., τόξων εὖ εἰδώς cunning in the use of the bow; οἰωνῶν σάφα εἰδώς Od.: —χάριν εἰδέναι τινί to acknowledge a debt to another, thank him, Il., etc.:—the Imperat. in protestations, ἴστω Ζεὺς αὐτός be Zeus my witness, Il.; Doric ἴττω Ζεύς, ἴττω Ar.: —εἰδώς absol. one who knows, εἰδυίηι πάντʼ ἀγορεύω Il.; ἰδυίηισι πραπίδεσσι with knowing mind, Il. c. inf. to know how to do, Il., Attic with the part. to know that so and so is the case, ἴσθι μοι δώσων know that thou wilt give, Aesch.; τὸν Μῆδον ἴσμεν ἐλθόντα Thuc. οὐκ οἶδα εἰ, I know not whether, expresses disbelief, like Lat. nescio an non, οὐκ οἶδʼ ἂν εἰ πείσαιμι Eur. οἶδα or ἴσθι are often parenthetic, οἶδʼ ἐγώ Eur.; οἶδʼ ὅτι, οἶσθʼ ὅτι, ἴσθʼ ὅτι, πάρειμι Soph.; so, εὖ οἶδʼ ὅτι Dem.: —in Trag. also, οἶσθʼ ὃ δρᾶσον; equivalent to δρᾶσον — οἶσθʼ ὅ; do— knowʼst thou what? i. e. make haste and do; οἶσθʼ ὡς ποίησον, etc.