Yes and no. It means Frosti’s daughter because her father’s name is Frosti (Frosti is conjugated to Frosta to mean Frosti’s). All Icelandic “last names” work like that: made from the father’s name and ‘dottir’ or ‘son’. The name Frosti comes from a dwarf in the Eddur and yes is derived from the Icelandic/Old Norse word frost.
Frostadottir is a badass last name… Am I wrong to surmise that it means, “frost daughter”?
Yes and no. It means Frosti’s daughter because her father’s name is Frosti (Frosti is conjugated to Frosta to mean Frosti’s). All Icelandic “last names” work like that: made from the father’s name and ‘dottir’ or ‘son’. The name Frosti comes from a dwarf in the Eddur and yes is derived from the Icelandic/Old Norse word frost.
It’s a patronymic, so she has it because her father’s name is “Frosti”. But that name presumably comes from “frost”.