a 1 or A 
(ā)
(ā)n. pl. a's or A's also as or As
Idiom: 1. The first letter of the modern English alphabet.
2. Any of the speech sounds represented by the letter a.
3. The first in a series.
4. Something shaped like the letter A.
5. A The best or highest in quality or rank: grade A milk.
6. Music
a. The sixth tone in the scale of C major or the first tone in the relative minor scale.
b. A key or scale in which A is the tonic.
c. A written or printed note representing this tone.
d. A string, key, or pipe tuned to the pitch of this tone.
7. A One of the four major blood groups in the ABO system. Individuals with this blood group have the A antigen on the surface of their red blood cells, and the anti-B antibody in their blood serum.
from A to Z
Completely; thoroughly.
Marquee, Radio City Music HallOpened in 1932, Radio City Music Hall is a landmark in New York's Rockefeller Center.