olemus
Wiktionary, adj:
3. (mathematics, logic) having the property of soundness
7. founded in law; legal; valid; not defective.
a sound title to land

Merriam-Webster, adj:
3a: free from error, fallacy, or misapprehension
3b: exhibiting or based on thorough knowledge and experience
3d: logically valid and having true premises
3e: agreeing with accepted views : ORTHODOX
5: showing good judgment or sense

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