Nominal dollars show the bill; a real measure asks how much that bill actually buys.
Go deeper
A dollar total can rise because more goods and services were produced, because prices increased, or both. Nominal measures include those effects together. Real measures remove the estimated effect of price changes, helping reveal changes in production volume or purchasing power, depending on the measure being discussed.
The adjustment must use a price measure appropriate to the statistic. Real GDP, for example, is not calculated simply by subtracting consumer inflation from every component. BEA uses detailed price and quantity information. Real values are still estimates, and chained-dollar components do not always add exactly to the published total.
Make it concrete
Hypothetical example: a shop sells 100 identical items at $10, then 100 at $11. Nominal sales rise from $1,000 to $1,100. With this price change removed, sales volume is unchanged.
When you read a headline
Before comparing dollar amounts across years, check whether they are inflation-adjusted and which price index was used. Do not mix real and nominal values in one comparison.