noun
also gran·dad·dy ˈgranˌ ̷ ̷ ̷ ̷, -raan-
Etymology: grand (I) + daddy
1.
a. : grandfather
b. : one that is very old and venerable
a cottonwood tree that was a real granddaddy — Richard Bissell
2. : one that is the first, earliest, most ancient, or most venerable : one that has been in existence the longest
the granddaddy of all the manufacturers of ready-built dwellings — New Yorker
the granddaddy of midget-racing-car drivers
the granddaddy of all reptiles — R.E.R.Hall
also : something impressive (as in size, extent, or force)
hadn't ranch winters been kind enough prior to this granddaddy of winters — A.B.Guthrie