1) There are several compounds where ‘clog’ served as an adjective, describing objects that were made out of large pieces of wood.
1623 2 clogg stooles, South Cave. This item of furniture featured regularly in inventories of different kinds, occasionally contrasted with less primitive items of furniture: 1677 3 clog stooles and 3 joynte stoules, Selby. Such stools were not just blocks of wood though, for in 1799 William Metcalfe of Sessay Parks wrote in his diary our Peggy … hurt herself by tumbling off the clog-stool in the cheese house yesterday. One of the feet broke.