This is the 313th most frequent Icelandic word.
grein
The Icelandic word "grein" means "article," "branch," or "section" in English, depending on context.
In this sentence, 'grein' refers to a 'field' or 'branch' of study or expertise.
Nám er flókin grein sem krefst mikillar einbeitingar.
Study is a complex field that requires a lot of focus.
Here, 'grein' is used to mean 'article' as in a written work or piece of journalism.
Ég las nýlega áhugaverða grein í dagblaðinu.
I recently read an interesting article in the newspaper.
In this context, 'grein' means a 'branch' of a tree.