bóka (ON) verb

Literally ‘to book’; used figuratively of swearing on a book, usually thought to be a gospel or some other type of holy book. Testimony sworn on a book could be referred to as bókarvitni (q.v.), and several fourteenth- and fifteenth-century diplomas attest to oaths on books (ON bókareið).

swear on a book OIce Jó Mah 9
OIce Js Mah 11
ONorw FrL Rgb 25
ONorw MLL Mah 10 Refs:

CV; Fritzner; ONP; Páll Vídalín s.v. bókarvitni