From Longman Dictionary of Contemporary Englishgranddaddygrand‧dad‧dy /ˈɡrændædi/ noun [countable] SSFFAMILY American English another spelling of grandaddy
Examples from the Corpus
granddaddy• Her granddaddy came up here to farm in 1891, but her husband's family has been here longer.• My granddaddy and my daddy both were police chiefs in this town. 