User:Racconish/sandbox2

A may refer to:

Nouns

 * A, the first letter of the Latin alphabet.
 * a, an indefinite article.

Cristallography

 * unit cell length (a)

Electricity

 * A battery, a vacuum tube filament battery.

Biochemistry

 * Vitamin A, also called retinol, an essential human nutrient
 * Haplogroup A (mtDNA), a human mitochondrial DNA (mtDNA) haplogroup
 * Haplogroup A (Y-DNA), a Y-chromosomal DNA (Y-DNA) haplogroup
 * A+ and A-, human blood types
 * Adenine, nucleic acid
 * Alanine, amino acid
 * Adenosine, nucleoside
 * ATC code A, Alimentary tract and metabolism, a section of the Anatomical Therapeutic Chemical

Chemistry

 * "A" was formerly the chemical symbol for the element argon, which is now indicated by the symbol Ar.
 * activity (chemistry) (a)

Mathematics

 * The center of a hexagonal face of the Brillouin zone of a hexagonal lattice, in physics
 * the unique, or one of the, reciprocal lattice vector(s) (a*)
 * specific surface area (a)

Physics

 * * Adsorption (a)
 * Bohr radius (a0)
 * acceleration (a)
 * Anode, an electrode
 * attenuation coefficient (a)
 * thermal diffusivity (a)

Astronomy

 * A whitish-blue class of stars in the Morgan-Keenan system, see stellar classification
 * A January 1 through 15 discovery in the provisional designation of a comet (for example, C/1760 A1
 * The semi-major axis of an orbit

quantities and units

 * annum (a), for year
 * are (a), a unit of area equal to 100 square metres (redirects to hectare)
 * atto- (a), the SI prefix meaning 10−18
 * a', a measure for the attraction between particles in the Van der Waals equation
 * magnetic vector potential (A)
 * absorbance (A)
 * area (A)
 * A value (A), a measure of substituent effects on the stereochemistry of cyclohexane
 * Helmholtz free energy (A)
 * mass number (A)
 * pre-exponential factor (A)
 * rotational constant (A)
 * Hall coefficient (AH)
 * relative atomic mass (Ar)
 * ampere (A), the SI base unit of electric current
 * ångström (Å), a unit of length equal to 1 metres
 * chemical affinity (A)
 * gain (A)
 * Hamaker constant (A)
 * hyperfine coupling constant (a or A)
 * Richardson's constant (A)

Mathematics and logic

 * A numerical digit meaning ten in hexadecimal and other positional numeral systems with a radix of 11 or greater
 * Sometimes in blackboard bold represents the algebraic numbers ($$\mathbb{A}$$ (U+1D538 in Unicode)
 * Universal quantifier in symbolic logic (symbol ∀ or $$\forall$$ (an inverted letter A)
 * Mills' constant is represented by the symbol A
 * Glaisher–Kinkelin constant is also often represented by the symbol A

Computing

 * A*, a pathfinding algorithm
 * A-0 System, early computer compiler
 * A+ (programming language)
 * A Sharp (Axiom), properly known as "A#"
 * BASIC A+
 * , the HTML element for an anchor tag
 * A Sharp (.NET) (A port of Ada to the Microsoft .NET Platform)
 * The most basic of the three levels of web site accessibility measured by Web Content Accessibility Guidelines

Music

 * A (musical note), the sixth solfège note
 * A (band), a British rock band
 * A (Cass McCombs album)
 * A (Jethro Tull album)
 * "A" (song), a song by Ayumi Hamasaki
 * "A", song by Barenaked Ladies from Maybe You Should Drive
 * "A", song by Cartel from Chroma
 * "A", a song in the Dance Dance Revolution video game series, by DJ Amuro
 * A or Side A, the top or first side of a gramophone record

Literature

 * "A", major poem by 20th century author Louis Zukofsky
 * a, A Novel, by 20th century artist Andy Warhol
 * A, the name of the Fourth Raikage, the leader of Kumogakure in the Naruto manga series

Film

 * A (1965 film), a short film animated by Jan Lenica
 * A (1998 Indian film), a Kannada movie directed by Upendra
 * A (1998 Japanese film), a documentary film about a Buddhist sect called "A"
 * A (2002 film), a British documentary film

Film ratings

 * A, a rating in India's Central Board of Film Certification
 * A certificate, a film rating used by the Canadian motion picture rating system
 * A, a British Board of Film Classification rating used from 1912–1982, see History of British film certificates

Television

 * A!, a common internet abbreviation for Animaniacs
 * A (TV system), a Canadian television system formerly known as A-Channel

Linguistics

 * A and an, the indefinite article in English
 * A (kana), the Japanese kana あ and ア which may be used to represent Asia
 * A (Cyrillic), the first letter of the Cyrillic alphabet
 * , the IPA representation of the open front unrounded vowel
 * , the IPA representation of the open back unrounded vowel

Transport

 * A (New York City Subway service), also known as the "A Eighth Avenue Express"
 * A (S-train) a service on the S-train network in Copenhagen
 * Alton Railroad (reporting mark)
 * Line A (Prague Metro)

Ships

 * A (yacht), an 118-meter megayacht owned by Andrey Melnichenko
 * SMS A, a Kaiserliche Marine tanker

Other

 * A-Frame, a type of structure
 * A, the alternate name for Brfxxccxxmnpcccclllmmnprxvclmnckssqlbb11116, a Swedish child born in 1991
 * Agilent Technologies, with U.S. ticker symbol A
 * Anarchist symbolism, an A within a circle
 * An ace in a deck of playing cards
 * Alpha, (sometimes A) in Christian theology is a metaphor for the beginning/creation of time and matter
 * A series of paper sizes defined by ISO 216, e.g. A4, A5 sizes
 * A (grade), an academic grade
 * Sentinel Peak (Arizona), more commonly known as "A" Mountain for the man-made rock formation in the shape of the letter
 * Scarlet A, symbol for atheism adopted by the Out Campaign a public awareness initiated by Elizabeth Cornwell and Richard Dawkins