From King Dictionary of Contemporary English
Related topics: Family
granddadgrand‧dad /ˈɡrændæd/ noun [countable] SSFFAMILYthe usual American spelling of grandad
Examples from the Corpus
granddadNow I am a happy dad and granddad.Some early skinheads went awry & wore tie-dyed granddad vests.And finally Don't forget granddad - remember he's a father too!My granddad, who smoked like a chimney and lived to 97, was lucky enough never to encounter a promoter.