Nominal rate
An interest rate as quoted, before adjusting for compounding within the year or for inflation. It is the headline figure rather than what is actually earned or paid.
Nominal means stated. A nominal rate is the number written on the offer, and it becomes a meaningful quantity only after one of two adjustments: one for how often interest is added within the year, and one for inflation. Which adjustment is meant depends on the context, and the two senses are entirely separate.
In rate quoting, the nominal annual rate is the period rate multiplied by the number of periods. A card charging 2 percent a month has a nominal annual rate of 24 percent, and that multiplication quietly ignores the fact that unpaid interest starts earning interest of its own. Put the compounding back and the effective annual rate is 26.82 percent, which is the same conversion that sits behind an APY.
In investing and economics, nominal means before inflation. A bond paying 6 percent while prices rise 4 percent hands you a much smaller gain in buying power than the coupon suggests, and the real rate is what measures the difference.
The thing to avoid is treating a nominal rate as complete. Without a compounding frequency it cannot be converted into what you would actually pay, and without an inflation figure it cannot be judged. Two accounts quoting the same nominal rate and adding interest at different frequencies are not the same account.