stepbrother
n. (继母与其前夫或继父与其前妻所生的)哥哥,弟弟
Someone's stepbrother is the son of their stepfather or stepmother.
1. a son of your stepparent by a former marriage
One of his stepbrothers is called Walter, the other one was called Herbie.
母亲再婚后,他多了两哥哥,叫瓦尔特和赫比.