This is the 26th most frequent Finnish word.
muassa
"Muassa" means "along with" or "together with" in English.
The word "muassa" in this sentence is part of the phrase "muun muassa," which means "among other things." It's often used to indicate examples within a larger group.
Hänellä oli mukanaan monia esineitä, muun muassa kirjoja.
He had with him many items, among others books.
"Muassa" here is used as part of "muiden muassa," meaning "among others." It's used to express inclusion within a group.
Minäkin käyn siellä muiden muassa.
I also go there among others.
In this sentence, "muassa" means "together with," showing companionship or presence with someone.