"They write a new dictionary every year."

Translation: De skriver en ny ordbok hvert år.

[ellasm123]

What's the difference between hvert and hver?

[FlFstur]

«Et år» is a neuter substantive, so whatever adjective you add to it, must be neuter too, in this case hvert instead of hver

[pantzo84]

Why is it ei? Is ordbook feminine?

[Deliciae]

'Bok' can be either feminine or masculine, as can 'ordbok' and any other compound noun which has 'bok' placed last.

[CaptainSeaweed]

Fascinating! Are there any other words that can be either masculine or feminine?