This is the 25th most frequent Icelandic word.
dag
"Dag" in Icelandic means "day" in English.
Here, "dag" refers to a full day, emphasizing the general experience of that day being pleasant.
Ég átti góðan dag.
I had a good day.
In this sentence, "dag" is used to mean a particular day in the past where an event occurred.
Við hittumst einn dag.
We met one day.
Here, "dag" refers to each individual day within a recurring pattern (in the context of the winter described).