A keyword is for 1 app and 1 country. Once it is tracked, it will give you an overview of that keyword’s ranking history in the specific country selected for the app chosen, as well as its associated competition (how hard it is to get into the top 10 in search results) and popularity scores (how popular is this keyword in the country chosen). You will also have an indication of installs derived from that keyword for that app.
If you wish to see how an app is ranked for a specific keyword across multiple countries, you will need to track that keyword in each of those countries. So, for instance, if you want to see how Spotify is performing for the keyword ‘Music’ in the US, Germany and United Kingdom, that will count as 3 keywords.