Extended Strong's Greek Lexicon (Abbott-Smith based)
oath
Usage: ὁρκωμοσία, -ας, ἡ (ὅρκος, ὄμνυμι; by metapl. for τὰ ὁρκωμόσια, asseverations on oath; see MM, xviii), [in LXX: Eze.17:18-19 (עָלָה) 1Es 9:93* ;] affirmation on oath, an oath: Heb.7:20-21, 28.† (AS)