Conscious understanding of something.
That which is detected by the five senses; not necessarily understood (imagine looking through fog, trying to understand if you see a small dog or a cat); also that which is detected within consciousness as a thought, intuition, deduction, etc.
Vision (ability)
The organisation, identification and interpretation of sensory information.
Acuity
The result or product of being sound.
The property (of an argument) of not only being valid, but also of having true premises.
The property of a logical theory that whenever a wff is a theorem then it must also be valid. Symbolically, letting T represent a theory within logic L, this can be represented as the property that whenever T⊢𝜙 is true, then T vDash 𝜙 must also be true, for any wff φ of logic L.
The state or quality of being sound.