a firm object or substance that has a fixed shape, not a gas or liquid:
the properties of liquids and solids
foods that are not liquid:
He's still too ill to eat solids.
3 [countable] technical
the part of a liquid which has the qualities of a solid when it is separated from the solvent (=watery part)
4 [countable] technicalHMCF
a shape which has length, width, and height, such as a sphere or cylinder