Word Origin & History
early 15c., from grand
. Replaced O.E. ealdefæder. The use of grand- in compounds, with the sense of "a generation older than, or younger than," is first attested early 13c., in Anglo-Fr. graund dame "grandmother." Latin and Greek
had similar usages. Grandmother also first attested early 15c., from M.Fr.; grandchild, grandson are later (16c.). The verb grandfather is from 1900. Grandfather clock is c.1880, from the popular song; they were previously known as tall case clocks or eight-day clocks.