a

: the first letter of the English alphabet

: a musical note or key referred to by the letter A : the sixth tone of a C-major scale

[count] : a grade that is given to a student for doing excellent work

[noncount] — used to refer to the first of two or more people, places, or things that are being considered

— used before singular nouns when the person or thing is being mentioned for the first time

a  — used like one before number words like hundred, thousand, etc.

b  — used like one before number words like third, fortieth, etc.

c  — used like one before units of weight, measurement, etc.

d  : one single : even one — used in negative constructions

— used before a word or phrase that indicates a type or class of person or thing — often used before noncount nouns that are modified by an adjective or phrase

— used like any to refer in a general way to people or things

— used before a proper noun to indicate limited knowledge about the person or thing being mentioned

a  — used before a proper noun that is acting as an example or type

b  — used before the name of a day of the week to refer to one occurrence of it

a  — used before the name of a person (such as a famous artist) when the name is being used to refer to something (such as a painting) created by that person

b  — used before a family name to show that someone is a member of that family

— used before a proper noun referring to a person or thing that has a particular quality

— used with words like bit and little to form phrases that describe quantity, amount, or degree

— used in phrases that describe how often something occurs, how fast something is going, etc.