This is the 959th most frequent Icelandic word.
þið
"Þið" means "you" (plural) in English.
Here "þið" is used as the subject pronoun referring to a group of people being addressed by the speaker.
Þið farið á bókasafnið saman.
You (plural) are going to the library together.
The word "þið" is used as the subject pronoun addressing multiple people in a question.
Hefur þið lokið matnum?
Have you (plural) finished your food?
Here "þið" serves as the subject pronoun addressing multiple individuals responsible for action.