From DMJ Productions
Haitian brothers

A sibling is a relative that shares at least one parent with the subject. A male sibling is a brother and a female sibling is a sister. A person with no siblings is an only child.

While some circumstances can cause siblings to be raised separately (such as foster care), most societies have siblings grow up together. This causes the development of strong emotional bonds, with siblinghood considered a unique type of relationship unto itself.

From Wikipedia