To the definitions already published I add that 'a' is also a preposition, an area symbol, or the prefix for atto ("factor of 10 8315;¹ 8312;"); and 'A' is the letter that in biochemistry represents adenine and alanine, is the symbol of the ampere , is the equivalent to decimal 10 in bases greater than 10, or the musical note in Anglo-Saxon notation.
a - refers to: 1 ) first letter of the Spanish alphabet - 41-2; in chemistry, represents the atomic mass - 41 3; It is one of the types of vitamins-41-4; It is one of the four fundamental blood groups - 5 ) It is the first side of a vinyl-41-6 record; in football, in some countries, means '' first division '' - 7 ) inside parentheses, and lowercase means '' alias ''. -Vitamin A or retinol is a substance indispensable for human life-
