A, or a, is the first , plural . this is the similar in brand to a Ancient Greek letter alpha, from which it derives. The uppercase representation consists of the two slanting sides of a triangle, crossed in the middle by a horizontal bar. The lowercase report can be total in two forms: the double-storey a together with single-storey ɑ. The latter is usually used in handwriting & fonts based on it, especially fonts included to be read by children, and is also found in italic type.

In the English grammar, "an", are indefinite articles.

Other uses

In algebra, the letter a along with various other letters of the alphabet is often used to denote a variable, with various conventional meanings in different areas of mathematics. Moreover, in 1637, René Descartes "invented the convention of representing unknowns in equations by x, y, and z, and knowns by a, b, and c", and this convention is still often followed, especially in elementary algebra.

In rays, etc. A capital A is also typically used as one of the letters to represent an angle in a triangle, the lowercase a representing the side opposite angle A.

"A" is often used to denote something or someone of a better or more prestigious vintage or status: A−, A or A+, the best grade that can be assigned by teachers for students' schoolwork; "A grade" for clean restaurants; A-list celebrities, etc. such associations can make-up a motivating effect, as exposure to the letter A has been found to modernizing performance, when compared with other letters.

"A" is used as a prefix on some words, such as asymmetry, to mean "not" or "without" from Greek.

In English grammar, "a", and its variant "an", is an indefinite article, used to introduce noun phrases.

Finally, the letter A is used to denote size, as in a narrow size shoe, or a small cup size in a brassiere.