A

art. indefinite article used with nouns

n. first letter of the English alphabet; first letter in the Latin alphabet

The letter A is the first letter in the Latin alphabet. Its name in English is a , plural aes, as, or a's.
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(a-acute) is a letter of the Faroese, Hungarian, Icelandic, Czech, and Slovak languages. This letter also appears in Irish, Occitan, Portuguese, Spanish, and Vietnamese language as a variant of the letter “a”.
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(a-circumflex) is a letter of Romanian and Vietnamese language. This letter also appears in French, Portuguese, Friulian and Walon language as a variant of the letter “a”.
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In Portuguese, the character Ã/ã represents a nasal central unrounded vowel, normally transcribed in IPA as (its exact height varies from open to mid according to the speaker's dialect). Because it is a typically Portuguese character, it is sometimes used as a symbol of the Portuguese language.Portuguese has five nasal vowels: (ã, an, am) (en, em) (in, im) (õ, on, om) (un, um)As well as five nasal diphthongs: (ãe) (ão, -am) (-em, -en-) (õe) (ui)
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"Ä", or "ä", is a character which represents either a letter from several extended Latin alphabets, or the letter A with umlaut or diaeresis.
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The letter Å represents various ò sounds in the Swedish, Finnish, Danish, Norwegian, North Frisian, Walloon, Chamorro and Istro-Romanian language alphabets. Other alphabets using the letter include the Lule Sami, Skolt Sami and Southern Sami alphabet.Å is often perceived as an A with a ring, interpreting the ring as a diacritical mark. However, in the languages that use it, the ring is not considered a diacritic but part of the letter. It developed as a form of semi-ligature of an A with another smaller a above it to denote a long a, similar to how the umlaut mark ¨ is developed from a small e written above the letter in question.
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Ă (upper case) or ă (lower case), usually referred to in English as A-breve, is a letter used in standard Romanian language and Vietnamese language orthographies. In Romanian, it is used to represent the mid-central unrounded vowel, while in Vietnamese it represents the short a sound. It is the second letter of both the Romanian and the Vietnamese alphabets.
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In computer science, A* (pronounced “A star”) is a graph/tree search algorithm that finds a path from a given initial node to a given goal node (or one passing a given goal test). It employs a “heuristic estimate” that ranks each node by an estimate of the best route that goes through that node. It visits the nodes in order of this heuristic estimate. The A* algorithm is therefore an example of best-first search.
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A+ may refer to:A+ (blood type), a blood typeA+ (grade), the highest grade achievable in a grading system based on letters of the alphabet.A+ (programming language), a dialect of APL with aggressive extensionsA+ (rapper), Andre Levins, an American rapperA-Plus (rapper), Adam Carter, an American rapperA+ certification, the professional computer technician certification by CompTIAAnimax Hungary, a Hungarian anime TV channel formerly known as A+A-Plus, an American convenience store chain owned & operated by SunocoA+ (magazine), covering Apple Computer software and hardware products, published in the 1980s by Ziff-Davis
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A++ stands for abstraction plus reference plus synthesis which is used as a name for the minimalistic programming language that is built on ARS.ARS is an abstraction from the Lambda Calculus, taking its three basic operations, and giving them a more general meaning, thus providing a foundation for the three major programming paradigms: functional programming, object-oriented programming and  imperative programming.ARS Based Programming is used as a name for programming which consists mainly of applying patterns derived from ARS, to programming in any language.
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A- can be:A- (plane), a U.S. military aircraft prefix.A- blood, blood type A negative.A- grade, a letter grade in the four point grade system, above 'B+', but below an 'A' (see Grade (education)).Privative a, a prefix expressing negation.Ā
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Bell character is an ASCII control character, code 7 (^G). When it is sent to a printer or a terminal, nothing is printed, but an audible signal is emitted instead. Terminal emulator windows often flash briefly to show the user where the alert occurred.A bell code also exists in Baudot code, which has been used in teleprinters in some form since 1874. Sending a bell code would get the attention of the teleprinter operator at the other end of the line.In the C programming language, the bell character is represented as '\a' ("alert" or "audible"). In Unicode, there is a character for visual representation of bell character, ”symbol for bell“, U+2407 — not to be confused with the actual bell character, U+0007.
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A floppy disk is a data storage device that is composed of a disk of thin, flexible ("floppy") magnetic storage medium encased in a square or rectangular plastic shell. Floppy disks are read and written by a floppy disk drive or FDD, the initials of which should not be confused with "fixed disk drive", which is another term for a hard disk drive. Invented by IBM, floppy disks in 8", 5.25", and 3.5" formats enjoyed many years as a popular and ubiquitous form of data storage and exchange, from the middle 1970s to the late 1990s. However, they have now been largely superseded by Flash and optical storage devices while email has become the preferred method of exchanging small to medium digital files.
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The grave accent ( ` ) is a diacritical mark used in written Catalan, French, Greek until 1982 (polytonic orthography), Italian, Norwegian, Occitan, Portuguese, Scottish Gaelic, Vietnamese, Welsh, and other languages.The word grave is derived from the Latin gravis (heavy). In English the word is normally pronounced "grahv", IPA , not like grave meaning "serious" or a "tomb." It comes from French, where it is pronounced similarly: accent grave .
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The ogonek (Polish for "little tail", the diminutive of ogon) is a diacritic hook placed under the lower right corner of a vowel in the Latin alphabet used in several European and Native American languages.
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A accommodation ; adenine or adenosine ; alanine ; ampere ; anode ; anterior. A / A / absorbance ; activity ; area ; mass number. [more]A - Community and Resources

Noun
1. the blood group whose red cells carry the A antigen
(synonym) type A, group A
(hypernym) blood group, blood type
2. a metric unit of length equal to one ten billionth of a meter (or 0.0001 micron); used to specify wavelengths of electromagnetic radiation
(synonym) angstrom, angstrom unit
(hypernym) metric linear unit
(part-holonym) nanometer, nanometre, nm, millimicron, micromillimeter, micromillimetre
(part-meronym) picometer, picometre, micromicron
3. any of several fat-soluble vitamins essential for normal vision; prevents night blindness or inflammation or dryness of the eyes
(synonym) vitamin A, antiophthalmic factor, axerophthol
(hypernym) fat-soluble vitamin
(hyponym) vitamin A1, retinol
4. one of the four nucleotides used in building DNA; all four nucleotides have a common phosphate group and a sugar (ribose)
(synonym) deoxyadenosine monophosphate
(hypernym) nucleotide
5. (biochemistry) purine base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNA
(synonym) adenine
(hypernym) purine
(substance-holonym) deoxyribonucleic acid, desoxyribonucleic acid, DNA
(classification) biochemistry
6. the basic unit of electric current adopted under the Systeme International d'Unites; "a typical household circuit carries 15 to 50 amps"
(synonym) ampere, amp
(hypernym) current unit
(part-holonym) abampere, abamp
(part-meronym) milliampere, mA
7. the 1st letter of the Roman alphabet
(hypernym) letter, letter of the alphabet, alphabetic character
(member-holonym) Roman alphabet, Latin alphabet

n. a, first letter of the Latin alphabet; first letter of the German alphabet

n. a umlaut, German vocal

prep. at (French)