- a grandson of one's nephew or niece.
Examples from the Web for great-grandnephew
Historical Examples of great-grandnephew
Colonel Washington was a great-grandnephew of George Washington.John Brown, Soldier of Fortune
Hill Peebles Wilson
He was the only surviving blood-relative of Paul Jones in this country, being his great-grandnephew.South American Fights and Fighters
Cyrus Townsend Brady
His great-grandnephew, our Sir Thomas, has celebrated his praise in very high terms.Sir Thomas Urquhart of Cromartie, Knight