A person's great-grandparent's "parents" would be that person's "great-great-grandparents". Commonly the prefix "great-" is added, one for each additional generation. To avoid having to add several "greats" when discussing a direct ancestors, ordinals are commonly used instead. For example, a "great-great-grandfather" would be a "second great-grandfather". A "great-great-great-grandfather" would be a third great-grandfather, and so on. Some sources also use cardinal numbers for numbering greats. For example, a great-great-great-great-great-great-grandmother becomes "six times great grandmother". However, sixth great-grandmother would be most commonly used.