She ate a piece of bread at the table.

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What does 'a piece of bread' mean?
1. a small piece of bread
2. a big piece of bread
3. whole bread such as a sandwich

Most likely, #1 is what's meant.

Think about when your parents cut you a piece of bread. Is it small, big, or huge? For me it would be #1, sadly.

The phrase "a piece of bread" typically refers to a small portion of bread. However, the exact size can vary depending on the context. It could be a small slice or a chunk of bread. To determine the exact meaning in a specific situation, you can consider the context and any additional details provided.