Primary Exchange

You want to visit Spain. But you can’t just “visit Spain.” Spain is a huge country. You have to go somewhere specific in Spain. You can visit Madrid, you can visit Barcelona, you can go to some out-of-the-way place in the Basque backcountry.

The question becomes: if you’re just going to spend three days in Spain, where exactly are you going to visit? What specific place in the country can you go to get a good idea of what "Spain" is like in general?

Similarly, if you say, "the Spanish stock market did well today," it may sound like you’re making a general statement. But you’re actually talking about something quite specific. You were talking about an individual index tracking the performance of an individual exchange. However, you are using this specific exchange as a stand-in for the country as a whole.

Each country's main stock exchange (the one you're referring to when you say that country's stock did this or that), is known as its primary exchange. The London exchange for the U.K. Paris for France. Madrid for Spain. Frankfurt for Germany. And so on.