or grandfather clock
a pendulum floor clock having a case as tall as or taller than a person; tall-case clock; long-case clock.
Origin of grandfather's clock
First recorded in 1890–95
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
any of various types of long-pendulum clocks in tall standing wooden cases, usually between six and eight feet tallAlso called: longcase clock
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012