granddaddy

1. (informal) A grandfather.Synonyms: gramps, popsinformal

2. (informal) Something that is the greatest or most significant of its kind.Examples: "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 ..."Synonyms: mother, father, grandfather, grandmammyinformal