What is "bone meal"

n. Ground bones used as a slow-release fertilizer, especially for bulbs.

Bone meal (or Bone manure) is a mixture of finely and coarsely ground animal bones and slaughter-house waste products. It is used as an organic fertilizer for plants and as a nutritional supplement for animals. As a slow-release fertilizer, bone meal is primarily used as a source of phosphorus and protein. Finely ground bone meal may provide a quicker release of nutrients than the coarser ground version of bone meal.