A

Latin alphabet
	A	B	C	D
E	F	G	H	I	J
K	L	M	N	O	P
Q	R	S	T	U	V
	W	X	Y	Z

The letter A is the first letter in the Latin alphabet.

Table of contents

1 History
2 Typography
3 Usage
4 Meanings for A
5 See also

History

The letter A probably started as a pictogram of an ox head in Egyptian hieroglyphs or the Proto-semitic alphabet.

Egyptian hieroglyphic ox head
Proto-semitic ox head Phoenician aleph Greek alpha Etruscan A Roman A
Egyptian hieroglyph
ox head Proto-semitic
ox head Phoenician aleph Greek alpha Etruscan A Roman A

By 1500 BC, the Phoenicians had given the letter a linear form that served as the basis for all later forms. Its name must have corresponded closely to the Hebrew aleph.

When the Ancient Greeks adopted the alphabet, they had no use for the glottal stop that the letter had denoted in Phoenician and other Semitic languages, so they used the sign for the vowel /a/, and changed its name to alpha. In the earliest Greek inscriptions, dating to the 8th century BC, the letter rests upon its side, but in the Greek alphabet of later times it generally resembles the modern capital letter, although many local varieties can be distinguished by the shortening of one leg, or by the angle at which the cross line is set.

The Etruscans brought the Greek alphabet to what is now Italy and left the letter unchanged. The Romans later adopted the Etruscan alphabet to write Latin, and the resulting letter was preserved in the modern Latin alphabet used to write many languages, including English.

Typography

The modern lowercase letter a derives from Greek handwriting, which evolved from a form similar to the current capital to a circular shape with a projection by the 4th century.

Blackletter A Uncial A Another Capital A
Blackletter A Uncial A
Modern Roman A Modern Italic A Modern Script A
Modern Roman A Modern Italic A Modern Script A

Usage

In English, the letter A by itself usual denotes the lax open front unrounded vowel (IPA /æ/), as in pad, the open back unrounded (IPA /ɑ/) or, in concert with a later e, the diphthong [Ej] (though the actual pronunciation depends on the dialect), as in ace, due to effects of the Great vowel shift.

In most other languages that use the Latin alphabet, the letter a denotes either a open central unrounded vowel (IPA /a/), or an open back unrounded vowel (IPA /ɑ/.

In the International Phonetic Alphabet, variants of the letter A denote various vowels. In X-SAMPA, capital A denotes the open back unrounded vowel and lowercase a denotes the open front unrounded vowel.

Alpha represents the letter A in the NATO phonetic alphabet.

The ASCII code for capital A is 65 and for lowercase a is 97.

Meanings for A

In baseball, the Oakland Athletics are often simply referred to as the "A's".
In biochemistry, A is the symbol for alanine and adenosine.
In calendars, A is often an abbreviation for the months April and August.
In computing, <A> is the HTML element for an anchor tag.
In education, a grade of A typically represents the highest score that students can achieve. (sometimes coupled with a plus sign - i.e., A+, or a number - e.g., A1)
In electronics, A is the heater (filament) power supply (originally a battery) of vacuum tube circuitry.
In film, A is an Italian film made in 1969; see A (film).
In financial securities, A is the stock symbol for Agilent Technologies.
In English, the word "a" is an indefinite article, see A, an
In Greek, a- is a prefix (alpha privativum) meaning "not" or "devoid of", used in many borrowed words in English, German and Romance languages.
In international licence plate codes, A stands for Austria.
In logic,
- the letter A is used as a symbol for the universal affirmative proposition in the general form "all x is y". The letters I, E and O are used respectively for the particular affirmative "some x is y", the universal negative "no x is y", and the particular negative "some x is not y". The use of these letters is generally derived from the vowels of the two Latin verbs affirmo (or AIo), "I assert", and nego, "I deny". The use of the symbols dates from the 13th century, though some authorities trace their origin to the Greek logicians.
- In symbolic logic, the symbol ∀ (an inverted letter A) is the universal quantifier.
In mathematics,
- A is often used as a digit meaning ten in hexadecimal and other positional numeral systems with a radix of 11 or greater,
- blackboard bold sometimes represents the algebraic numbers.
In medicine, A is one of the human blood types.
In the Metric system,
- A is the symbol for the ampere or amp, the SI base unit of electric current.
- a, atto, is the SI prefix meaning 10^-18
- a is the symbol for the are, a unit of surface area equal to 100 square metres.
In music, A is a note, A is an album by Jethro Tull; see A (album), and A is a British rock band; see A (band)


Egyptian hieroglyph ox head	Proto-semitic ox head	Phoenician aleph	Greek alpha	Etruscan A	Roman A


Blackletter A	Uncial A

Modern Roman A	Modern Italic A	Modern Script A