grandfather clock

The terms grandfather clock, grandmother clock, and granddaughter clock are popular names for longcase clocks.

Although the terms are used imprecisely, the generally accepted convention is that a clock less than 5 feet (150 cm) in height is a granddaughter; one between 5 feet (150 cm) and 6 feet (180 cm) is a grandmother; and one over 6 feet (180 cm) is a grandfather.