What is Parallel and cross cousins?

In discussing consanguineal kinship in anthropology, a parallel cousin or ortho-cousin is a cousin from a parent's same-sex sibling, while a cross-cousin is from a parent's opposite-sex sibling. Thus, a parallel cousin is the child of the father's brother or of the mother's sister , while a cross-cousin is the child of the mother's brother or of the father's sister. Where there are unilineal descent groups in a society , one's parallel cousins on one or both sides will belong to one's own descent group, while cross-cousins will not.