Grandparent

Grandparent was a name used to describe one's ancestor, namely the parent of one's parent, where the subject in question would be the grandparent's grandchild. (TV: Partners in Crime) Each previous generation of the initial grandparent was given the qualifier of "great", which was then compounded. (TV: The Cambridge Spy)

The First Doctor was Susan Foreman's grandfather. (TV: "An Unearthly Child") At the time they escaped Gallifrey, Stoyn expressed that "no one has grandfathers these days". (AUDIO: The Beginning)

As the father of Sylvia Noble, Wilfred Mott was the grandfather of her daughter Donna Noble. (TV: Partners in Crime)

William Pike was the grandfather of Harry Pike, and so the great-grandfather of his son Darius Pike. (TV: The Cambridge Spy, The Last Precinct)

Jack Harkness was the grandfather of Steven Carter. By 2009, Jack appeared younger than Steven's mother, Alice Carter. Because of this, Alice led Steven to believe Jack was actually his uncle rather than explain his grandfather's Immortality. (TV: Children of Earth: Day One)

The term was traditionally used for the founder of a Great House. For instance, the founder of House Paradox was called "Grandfather Paradox", and the founder of House Halfling was called "Grandfather Halfling". (PROSE: The Book of the War)