Emily Dickinson Lexicon

SOUND'NESS, n.

1. Wholeness; entireness; an unbroken, unimpaired or undecayed state; as, the soundness of timber, of fruit, of the teeth, of a limb, &c. [See Sοund.]
2. An unimpaired state of an animal or vegetable body; a state in which the organs are entire and regularly perform their functions. We say, the soundness of the body, the soundness of the constitution, the soundness of health.
3. Firmness; strength; solidity; truth; as, soundness of reasoning or argument, of doctrine or principles.
4. Truth; rectitude; firmness; freedom from error or fallacy; orthodoxy; as, soundness of faith.