Wiktionary
great grandchildren
n. (great grandchild lang=en nodot=1) ((alternative spelling of great-grandchildren lang=en nocap=1 nodot=1)).
Usage examples of "great grandchildren".
When it was said he deserved to be known as the father of the American navy, Adams answered that he was father of enough as it was, with two sons, fourteen grandchildren, and five great grandchildren, all of whom required his attention and support.