The highest rank on any of various scales that assign letters.
Bond rating
(education) The highest letter grade assigned (disregarding plusses and minuses).
(music) A tone three fifths above C in the cycle of fifths; the sixth tone of the C major scale; the first note of the minor scale of A minor; the reference tone that occurs at exactly 440 Hz; the printed or written note A; the scale with A as its keynote.
(medicine) A blood type that has a specific antigen that aggravates the immune response in people with type B antigen in their blood. They may receive blood from type A or type O but cannot receive blood from AB or B.
We assign each item inspected a rating from A through G, depending on various factors.
I was so happy to get an A on that test.
Orchestras traditionally tune to a concert A.
My blood type is A negative.
In particular, the other three A’s in the deck and the other three K’s would give you a hand that beats Q’s. The probability that you will end up with the winning hand is 13.6 percent.