granddaddy

noun

1. (informal)A grandfather.
2. (informal)Something that is the greatest or most significant of its kind.

   “The nature of this gas enables it to absorb the majority of the sun's ultraviolet rays, thus saving the human race from the granddaddy of all sunburns.”

   “In the far corner, representing the twentieth century, is the granddaddy of all common stocks, AT&T. Here is a company that earned its place in the pantheon of great stocks simply by increasing its dividend for an absurdly long period of time.”

   “The region, with its twenty-two hours of summer daylight, is now known for its giant vegetables that include six-foot-wide cauliflower, eighteen-pound carrots, fifty-pound celery, and the granddaddy of all giant vegetables, the Alaskan cabbage ...”

   “A hundred years from now or two-hundred years from now they will speak of this tsunami of all tsunami's— the granddaddy of all tsunami's.”