Dictionary entry

ὅρκος

G. Abbott-Smith's A Manual Greek Lexicon of the New Testament

ὅρκος, -ου, ὁ,

[in LXX chiefly for שֶׁבַע, שִׁבְעָה and cogn. forms;]

an oath: Mt 14:726:72, Lk 1:73, Ac 2:30, He 6:16, 17, Ja 5:12; p1., Mt 5:33(LXX)14:9, Mk 6:26.†