ὁρκωμοσίαhorkōmosía

Same root

• ὅρκοςhórkos · G3727perhaps akin to G3725 (ὅριον)); a limit, i.e. (sacred) restraint (specially, an oath)
• ὀμνύωomnýō · G3660to swear, i.e. take (or declare on) oath

Where it appears

Appears 3 times in the Bible.

• Hebrews 7:20 This new system was established with a solemn oath. Aaron’s descendants became priests without such an oath,
• Hebrews 7:21 but there was an oath regarding Jesus. For God said to him, “The Lord has taken an oath and will not break his vow: ‘You are a priest forever.’”
• Hebrews 7:28 The law appointed high priests who were limited by human weakness. But after the law was given, God appointed his Son with an oath, and his Son has been made the perfect High Priest forever.