- an uncle of one's grandfather or grandmother.
Origin of great-granduncle
First recorded in 1800–10
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for great-granduncle
And that he most likely inherited from his great-granduncle.Dave Porter in the Far North
One night—the hundredth time—he teased Tabitha to tell him something new about his great-granduncle.Twice Told Tales
One night, the hundredth time, he teased Tabitha to tell him something new about his great-granduncle.Twice-Told Tales