This is the 644th most frequent Finnish word.
jalkapallon
"Jalkapallon" means "of football" or "of soccer" in English, showing possession.
The word 'jalkapallon' here is in the partitive case, indicating an object (the soccer ball) that is being purchased.
Ostin uuden jalkapallon eilen.
I bought a new soccer ball yesterday.
The word 'jalkapallon' functions here as a genitive modifier describing 'mestaruuskilpailuissa', specifying whose championship is being referred to.
Pelaamme jalkapallon mestaruuskilpailuissa ensi viikolla.
We will play in the soccer championship next week.
The word 'jalkapallon' is in the genitive case here to show possession or relationship to the location context next to the soccer ball.