What Does “Brothers of Jesus” Mean in the Bible?
That is what the Bible calls some close relatives of Jesus. The Church teaches that they were not children of the Virgin Mary.
Today
In Hebrew and Aramaic, “brother” was also said of cousins and other relatives.
Where it appears in the Bible
Mark 6:3; Matthew 13:55
What the Bible says
Mark 6:3
Is not this the carpenter, the son of Mary, the brother of James, and Joseph, and Jude, and Simon? are not also his sisters here with us? And they were scandalized in regard of him.
Matthew 13:55
Is not this the carpenter’s son? Is not his mother called Mary, and his brethren James, and Joseph, and Simon, and Jude:
Douay-Rheims Bible (Challoner revision), public domain.
Source: Catechism 500; Catholic Encyclopedia (1913), “Brethren of the Lord, The”