This is the 2nd most frequent Icelandic word.
í
The Icelandic word "í" means "in" or "into" in English.
Here, 'í' is used as a preposition meaning 'in', indicating location within a place.
Ég er í Reykjavík.
I am in Reykjavik.
'Í' indicates movement or direction, equivalent to 'into' in English.
Hann setti bækurnar í bakpokann.
He put the books into the backpack.
The preposition 'í' is used in an idiomatic expression to indicate participation in an activity, similar to 'to go swimming' in English.