skýlihögg (ON) noun

A notch or cut made on wood which blemishes or defaces it. In the Icelandic laws these strikes are mentioned as damage to ships (Grg Feþ 166) and standing woodland (Grg Lbþ 199). The penalty for hacking notches in another’s timber was more severe in the case of ships (lesser outlawry) than for standing wood (a six-ounce fine). In addition to legal texts, the term appears in at least three sagas, including a verse in Grettis saga.

notch OIce Grg Feþ 166 Lbþ 199
OIce Jó Llb 19 Fml 16 Refs:

CV s.v. skýlihögg; Fritzner s.v. skýlihögg; GrgTr II:92 note 238; Hertzberg s.v. skýlihögg; Páll Vídalín 1854 s.v. skýlihögg