| # | Concept | Culture | Statement | Freq. |
|---|---|---|---|---|
| 1 | coal | United States | Historically significant as a major energy source for industrialization and electricity production | 1 |
| 2 | coal | United States | Historically used as a major source of energy and heat during the industrial revolution and beyond. | 1 |
| 3 | coal | United States | Historically important as a primary source of energy for industrial revolution and power generation | 1 |
| 4 | coal | United States | Used as a major source of energy and heat production | 1 |
| 5 | piece of coal | United States | Used for heating and power generation in colder regions | 1 |
| 6 | piece of coal | United States | Used for heating in some households, especially in colder regions | 1 |