A pendulum clock enclosed in a tall, narrow cabinet.
A large clock with a pendulum, contained in a tall, narrow case.
Origin of grandfather-clock
From the song My Grandfather's Clock by Henry Clay Work (1832–1884), American songwriter
American Heritage Dictionary of the English Language, 5th Edition
From a song by American songwriter Henry Work, based on a clock in the George Hotel, Yorkshire, England, which stopped keeping time after its owner died.