Hobbies are anything you do for fun in your free time. All games and sports are hobbies. Playing with toys or collecting stamps are also hobbies. You do hobbies because you find them fun. Hobbies are things you do when you are not at school or doing chores.
Some people that are really good at hobbies may go into a competition and some grown-ups even play sports for a job.
Sports are games which people play for fun and some grown-ups play as jobs. They can be played outside or sometimes inside in special gyms and indoor fields. Sports are different from other games because you have to do more running or lifting than other games. The most popular sport in the world is soccer, which is sometimes called football.