Lexical Definition

‎ὁρκωμοσία‎ horkōmosía (hor-ko-mos-ee'ah) oath G:N-F
from a compound of ‎ὅρκος‎ and a derivative of ‎ὀμνύω‎

oath.

Usage: 2 forms in 6 verses
Form Translated As     In Verse(s)
ὁρκωμοσίασ an oath Heb.7.20Heb.7.20Heb.7.21
oath Heb.7.28
ορκωμοσίαν swearing by my oath LXX.Ezek.17.19
swearing of an oath LXX.Ezek.17.18

Abbott-Smith

ὁρκωμοσία, -ας, ἡ (< ὅρκος, ὄμνυμι; by metapl. for τὰ ὁρκωμόσια, asseverations on oath; v. MM, xviii), [in LXX: Ez 17:18, 19 (אָלָה) I Es 9:93*;]
affirmation on oath, an oath: He 7:20, 21, 28.†

Abbott-Smith References

Book Refs
Ezekiel 17:18 · 17:19
Hebrews 7:20 · 7:21 · 7:28

Liddell-Scott-Jones

ὁρκωμοσία-ωμοσία, ,

swearing, oath, [LXX+NT+2nd c.AD+]

LSJ Scripture Refs: LXX.Ezek.17.18Heb.7.20