What do you call children who are related due to their parents marriage but neither have the same biological parent?

In a marriage in which both the husband and the wife have children from a previous marriage, the children are step-children to the parent who is not their bioloigical parent, and are step-siblings (step-brothers and step-sisters) to each other.
In a marriage in which both the husband and the wife have children from a previous marriage, the children are step-children to the parent who is not their bioloigical parent, and are step-siblings (step-brothers and step-sisters) to each other.