A Grandfather Clock. A long case clock, also tall-case clock, floor clock, or grandfather clock, is a tall, freestanding, weight-driven pendulum clock with the pendulum held inside the tower, or waist of the case. Clocks of this style are commonly 1.8–2.4 meters (6–8 feet) tall. The case often features elaborately carved ornamentation on the hood, or bonnet, which surrounds and frames the dial, or clock face.
The English clockmaker William Clement is credited with the development of this form in 1670.