You may have heard the term “foreign transaction fee” when you make purchases outside the United States.

Well, guess what? Some banks are expanding the definition of that term, so watch out.

Generally, a foreign transaction fee is levied when you use your credit card outside of the country.

Visa and MasterCard charge a 1 percent fee to convert the transaction from foreign currency into U.S. dollars, and banks can add another percentage on top of that.

As a result, travelers would come home to find exorbitant charges for every credit-card purchase they made.

Well, lately, some travelers have discovered similar charges even when they never left the country!

What’s happening is that certain banks, including Bank of America and Simmons, now charge the transaction fee for any transactions processed outside of the U.S.

So if your airline is based in Asia, or your cruise line is based in Europe, you get nailed with the fee. And in many cases, it may not be obvious where your travel provider does its banking.

Unfortunately, there’s no way around those fees if that’s the policy your bank has adopted. Your best bet is to stick with credit cards that charge no or low foreign transaction fees, such as Capital One.

And, like anything else, arm yourself with knowledge. Talk to a human being, and ask if there are any additional fees that you need to be aware of before handing over your credit card.

For more about spending money in foreign countries, check out the Money, Currency & Credit section.

And get more of our Daily Travel Tips here.