noun

A stepbrother is a boy who becomes your brother because his parent married one of your parents. He is not your brother from the same mom and dad, but he becomes part of your family when your parent marries his parent.

Example

1. My stepbrother and I love playing video games together after school.
2. Yesterday, my stepbrother helped me with my math homework.
3. On weekends, my stepbrother and I often go to the park to play soccer.