| ̷ ̷ ̷ ̷| ̷ ̷ ̷ ̷ adjective
: of or relating to a system of coal mining in which tunnels are driven in a checkerboard pattern having massive square pillars between them which are gradually cut away as the work proceeds
| ̷ ̷ ̷ ̷| ̷ ̷ ̷ ̷ adjective
: of or relating to a system of coal mining in which tunnels are driven in a checkerboard pattern having massive square pillars between them which are gradually cut away as the work proceeds
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012