This was too interesting not to share.
A kenning is a phrase that means the same thing as another phrase, usually something translated from old english or norse, or another old language. Sort of like a euphemism from old to modern.
For example, to ‘kill one’s enemies’ in our modern lingo is the same as saying ‘to feed the eagles’ in Swedish. That’s one of my favorites. Another is the term ‘battle-sweat’, Old English from Beowolf. It means blood, and to shed a lot of battle-sweat means to bleed a lot during a fight.
There’s a whole list of them on this wikipedia page. Enjoy!