👉 Grandchildren are children born to a parent and their spouse, who is usually an adult. These children are typically considered siblings of the birth parents due to the biological relationship established by their birth parents' marriage to each other. In some cultures or societies, the concept of "grandchildren" may extend further in depth to include grandchild cousins, nephews and nieces. The term can also be used to refer to the children born from a parent's previous marriage, which are considered siblings due to