From King Dictionary of Contemporary English
Related topics: Family
grandaddygran‧dad‧dy, granddaddy /ˈɡrændædi/ noun (plural grandaddies) [countable] American English informal 1 SSFFAMILYgrandfather2 the grandaddy of something
Examples from the Corpus
grandaddyHis grandaddy used to work for three dollars a day.Plenty of booze and chow round out the celebration, considered the grandaddy of July Fourth blasts.