This is the 15th most frequent Icelandic word.
þá
"Þá" means "then" in English.
Here, 'þá' is used to specify the time period during which the meeting took place, acting as a temporal adverb.
Við hittumst þá sem við vorum í skólanum.
We met then when we were in school.
In this case, 'þá' illustrates the sequence of events, functioning again as a temporal adverb.
Við munum fara þangað ef veðrið verður gott, og þá getum við líka heimsótt safnið.
We will go there if the weather is good, and then we can also visit the museum.
Here, 'þá' connects clauses, essentially meaning "so" or "therefore," showing a causal or logical consequence.