pillar working
Mining
noun
A working in which pillars are left in place.
Origin
Mid 19th century.
- opinion pollster
- opinion survey
- opinion trade
- opinious
- opioid
- opiomania
- O. Pip
- opisometer
- opisthe
- opisthion
- opistho-
- opisthobranch
- Opisthobranchia
- opisthobranchiate
- opisthocoelian
- opisthocoelous
- opisthodome
- opisthodomos
- opisthodomus
- opisthodont
- opisthogastric
- opisthoglyph
- opisthoglyphic
- opisthoglyphous
- opisthognathous