Definition of: solid

(sol′id) adjective
1. Having its constituent particles so firmly coherent as to resist stress; compact, firm, and unyielding: opposed to fluid.
2. Substantial; firm and stable.
3. Filling the whole of the space occupied by its apparent form; completely filled; not hollow.
4. Having no aperture or crevice; compact.
5. Manifesting strength and firmness; not weak or sickly; sound.
6. Characterized by reality; substantial or satisfactory.
7. Exhibiting united and unbroken characteristics, opinions, etc.; being or acting in unison; unanimous: the solid vote; This county is solid for the Democratic party; also, blindly or unreasonably partisan.
8. Financially sound or safe.
9. U.S. Colloq. Certain and safe in approval and support: They were solid with the boss.
10. Having or relating to the three dimensions of length, breadth, and thickness.
11. Written without a hyphen: said of a compound word. See SOLIDEME.
12. Cubic in shape: a solid yard.
13. Unadulterated; unalloyed: solid gold.
14. Carrying weight or conviction: a solid argument.
15. Serious; reliable; exhibiting sound judgment: a solid citizen.
16. Continuous; unbroken: a solid hour.
17. Printing Having no leads or slugs between the lines; not open. See synonyms under FIRM¹, HARD, IMPENETRABLE.
—noun
1. A mass of matter of which the shape cannot be changed permanently and greatly without fracture.
2. A magnitude that has length, breadth, and thickness, as a cone, cube, pyramid, prism, or sphere. [<F solide <L solidus]
—sol′id·ly adverb
—sol′id·ness noun