- the firmness and tone of healthy tissue "his muscle firmness"
- the quality of being prudent and sensible
- a state or condition free from damage or decay
1. The quality or state of being sound; as, the soundness of timber, of fruit, of the teeth, etc.; the soundness of reasoning or argument; soundness of faith.
Syn. -- Firmness; strength; solidity; healthiness; truth; rectitude.