This is the 7752nd most frequent Swedish word.
troja
Sweater or jersey.
Here, 'tröja' refers to a type of clothing, specifically a sweater.
Hon köpte en ny tröja till festen.
She bought a new sweater for the party.
In this sentence, 'tröja' is used to describe a preferred article of clothing, the sweater.
Min favorittröja är blå och vit.
My favorite sweater is blue and white.
The word 'tröja' here identifies the necessity for a specific kind of clothing suitable for cold weather.