じいさん Also written 爺さん, 祖父さん Meanings Noun grandfather (usu. 祖父さん; may be used after name as honorific) See also: おじいさん. male senior-citizen (usu. 爺さん; may be used after name as honorific) See also: じいちゃん. Related forms おじいさん grandfather (polite) Jinuma: Japanese Dictionary · Word lists