- a soft coal, usually dark brown, often having a distinct woodlike texture, and intermediate in density and carbon content between peat and bituminous coal.
- a brown carbonaceous sedimentary rock with woody texture that consists of accumulated layers of partially decomposed vegetation: used as a fuel. Fixed carbon content: 46–60 per cent; calorific value: 1.28 × 10 7 to 1.93 × 10 7 J/kg (5500 to 8300 Btu/lb)
