1. Plural of culm; coal dust or slack coal, especially the waste or inferior coal from coal mines.
Usage: chiefly British; industrial/mining term
2. Plural of culm; the hollow jointed stem of a grass or cereal plant, such as wheat or bamboo.
Usage: botany

Examples

• The miners sorted through culms to recover any usable coal fragments.
• Culms from the coal operation were dumped in large piles outside the mine.
• The culms of wheat plants are harvested along with the grain.
• Bamboo culms are strong and flexible, making them useful for construction.
• After threshing, the culms are often used as animal bedding or fuel.