This is the 1658th most frequent Polish word.
partię
"Partię" is the accusative form of "partia," meaning "party" (e.g., political party or game/match).
In this context, 'partię' means a 'game' of chess, referring to a single instance of a match.
Grałem w szachy i wygrałem partię.
I was playing chess and I won the game.
Here, 'partię' refers to a 'political party', signifying an organized group sharing political aims.
Partię polityczną, którą popieram, ma nowe propozycje.
The political party I support has new proposals.
In this instance, 'partię' means a 'part', specifying a section of a musical arrangement.