[mongol]

Yes and this is to this day the Swedish word for Saturday: lördag, from "lögardagen". Same etymology as laugardagr.

[kzrdude]

Well, laugardagr is the etymology, isn't it?

The modern shapes of this weekday name are still used in the scandinavian languages, and Icelandic, Finnish and Estonian.

[mongol]

Yes could be, it is obvious they are related, I don't know if laugardagr is the original or if they have common roots.

[Tagbert]

laugardagr is the Old Norse word. Swedish developed from Old Norse (as did Norwegian and Danish). The Swedish lördag is derived from laugardagr.

The “laug” portion comes from Old High German “louga”, from PIE root leue- "to wash."

The “dagr” portion comes from the PIE root agh- "a day" with an initial “d” added as part of Old High German. OHG is the ancestor of Old Norse.

This is from Etymonline - a great resource for language information https://www.etymonline.com/search?q=laug

[kzrdude]

I think mongol is right to be careful. There wasn't one coherent old Norse, it had east-west variation even then for example.

But it should give the broad strokes, just like talking about PIE is certainly a broad stroke.