Yes, solid is a Scrabble word!

Adjective

1. Characterized by good substantial quality

2. Of definite shape and volume; firm; neither liquid nor gaseous

3. Entirely of one substance with no holes inside

4. Of one substance or character throughout

5. Uninterrupted in space; having no gaps or breaks

6. Providing abundant nourishment

7. Of good quality and condition; solidly built

8. Not soft or yielding to pressure

9. Having three dimensions

10. Impenetrable for the eye

11. Financially sound

12. Of a substantial character and not frivolous or superficial

13. Meriting respect or esteem

14. Of the same color throughout

15. Acting together as a single undiversified whole

Noun

1. Matter that is solid at room temperature and pressure

2. The state in which a substance has no tendency to flow under moderate stress; resists forces (such as compression) that tend to deform it; and retains a definite size and shape

3. A three-dimensional shape