chirographum (ON) noun

A chirograph, a document on which the same text is written twice (or more) and subsequently divided and given to multiple parties as proof of a transaction. Chirographs are well attested in medieval Europe, in particular in England, whence this type of document likely spread to the Nordic countries. The oldest attested chirograph from Norway dates to 1225 (DN I nr. 8), and several others survive from Sweden, Norway, Denmark and Iceland, mostly from the later Middle Ages.

chirograph OIce Jó Kab 12
ONorw MLL Kab 11 Refs:

Beal 2008 s.v. chirograph; KLNM s.v. chirographum; LexMA s.v. chirograph