Suzerainty (American accent: soo-zer-en-tee) happens when a country X has its own government but cannot act independently because of a more powerful country Y. This more powerful country Y is called the suzerain and can usually control the foreign relations of X (how X interacts with other countries).
It differs from sovereignty in that the tributary still has limited control of its own stuff and internal country affairs.
Some examples change
The term suzerainty originally described the relationship between the Ottoman Empire and its surrounding regions including: