This is the 11317th most frequent Swedish word.
mässa
"Mässa" in Swedish can mean either a "mass" (religious ceremony) or a "fair" (exhibition).
In this sentence, 'mässan' is used to describe a fair or exhibition, specifically a book fair.
Vi ska gå till bokmässan i Göteborg nästa vecka.
We will go to the book fair in Göteborg next week.
Here, 'mässan' refers to a religious service or mass held in a church.
Den stora mässan i kyrkan började klockan tio.
The grand mass in the church started at ten o'clock.
In this case, 'mässan' denotes a trade fair or show where products or services are exhibited.