Tariffs are taxes charged on goods bought from other countries. Typically, they are a percentage of a product's value. So, a 15% tariff means that a $100 product imported to the US from the EU will have a $15 dollar tax added on top - taking the total cost to the importer to $115.

Both sides hailed the agreement as the biggest ever. But it will come at a cost to the European Union, and many details have yet to be nailed down.

The Europe trade deal will see the U.S. impose a 15% import tariff on most EU goods − half the threatened rate but much more than Europeans hoped for.