Understanding.
That which is accessible; that which is within one's reach or ability.
Grip.
To take advantage of something, to seize, to jump at a chance.
To grip; to take hold, particularly with the hand.
To understand.
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