Skúlin in Faroese means 'the school', skúli- being school and -n being the definite article. Some people have nicknames like í Skúlanum (in the school), which means that they probably had another surname, but since they were either relatives, servants or just residence of the local school, they'd get this nickname, since first names at the time were relatively few and very common.

Skúlin btw. is pronounced skew-lyn. (but don't add a y-sound before the ew in the first syllable).

Cheers, Johan Petur Dam