This is the 834th most frequent Spanish word.
pieza
"Piece," "part," or "room," depending on context.
In this usage, 'pieza' denotes 'an item or work', referring to a single instance or object within a broader category, such as an artwork.
Esa pintura es una pieza invaluable de arte.
That painting is an invaluable piece of art.
In this sentence, 'pieza' is used to mean 'a portion or piece' of something, specifically a piece of bread in the context.
Compré una pieza de pan para la cena.
I bought a piece of bread for dinner.
Here, 'pieza' refers to 'a game piece', which is a movable object used in board games like chess.