Foreign ownership means that someone who is not from the country holds the ownership or control over a property, asset or company in that country. For example, if you live in America and you own a toy store in Japan, you have foreign ownership of that store.
Imagine that you have a box of toys, and you want to let your friend play with them for a while. Your friend lives in another city, so you have to send the box to them. When you send the box away, it is now owned by your friend, and they can play with the toys until you ask for them back.
Similarly, when someone from another country buys or controls a company, property or asset in your country, they have foreign ownership. They can make decisions about it and do what they want with it, just like your friend can play with the toys in the box.
Foreign ownership can be good for countries because it can bring in money and create jobs. However, some people worry that foreign ownership can be a problem if it means that too much of a country's resources or companies are controlled by people who aren't from that country.