Powder, solids, dry matter, granular material, bulk material...
Bulk solids do not have an unambiguous name; it is not an unambiguous material.
Bulk solids do neither behave as a solid, nor a liquid, nor a gas.
A definition of this matter could be:
a number of particles that in principal can move freely, but that definitely show interaction and are also influenced by gases and/or liquids that are present between these particles.
Whatever it is called, through fundamental knowledge and years of experience BSE is specialist in the field that we call bulk technology.