a 1 or A ( )n. pl. a's or A's also as or As 1. The first letter of the modern English alphabet. 2. Any of the speech sounds represented by the letter a. 3. The first in a series. 4. Something shaped like the letter A. 5. A The best or highest in quality or rank: grade A milk. 6. Music a. The sixth tone in the scale of C major or the first tone in the relative minor scale. b. A key or scale in which A is the tonic. c. A written or printed note representing this tone. d. A string, key, or pipe tuned to the pitch of this tone. 7. A One of the four major blood groups in the ABO system. Individuals with this blood group have the A antigen on the surface of their red blood cells, and the anti-B antibody in their blood serum. Idiom: from A to Z Completely; thoroughly. |
a 2 ( ; when stressed)indef.art.1. Used before nouns and noun phrases that denote a single but unspecified person or thing: a region; a person. 2. Used before terms, such as few or many, that denote number, amount, quantity, or degree: only a few of the voters; a bit more rest; a little excited. 3. a. Used before a proper name to denote a type or a member of a class: the wisdom of a Socrates. b. Used before a mass noun to indicate a single type or example: a dry wine. 4. The same: birds of a feather. 5. Any: not a drop to drink.
[Middle English, variant of an, an; see an1.] Usage Note: In writing, the form a is used before a word beginning with a consonant sound, regardless of its spelling (a frog, a university). The form an is used before a word beginning with a vowel sound (an orange, an hour).·An was once a common variant before words beginning with h in which the first syllable was unstressed; thus 18th-century authors wrote either a historical or an historical but a history, not an history. This usage made sense in that people often did not pronounce the initial h in words such as historical and heroic, but by the late 19th century educated speakers usually pronounced initial h, and the practice of writing an before such words began to die out. Nowadays it survives primarily before the word historical. One may also come across it in the phrases an hysterectomy or an hereditary trait. These usages are acceptable in formal writing. |
a 3 ()prep. In every; to each; per: once a month; one dollar a pound.
[Middle English, from Old English an, in; see on.] |
a 4 ()aux.v. Informal Have: He'd a come if he could.
[Middle English, alteration of haven, to have; see have.] |
a 5abbr.1. acceleration 2. are (measurement) |
a or A Noun pl [a's, A's] or As 1. the first letter of the English alphabet 2. from A to B from one place to another: I just want a car that takes me from A to B 3. from A to Z from start to finish
a Adjective (indefinite article) 1. used preceding a singular count noun that has not been mentioned before: a book, a great shame 2. used preceding a noun or adjective of quantity: a litre of wine, a great amount has been written, I swim a lot and walk much more 3. each or every; per: I saw him once a week for six weeks
A 1. Music the sixth note of the scale of C major 2. ampere(s) 3. atomic: an A-bomb
A Abbreviation of adenine, ampere, angstrom, area |
ThesaurusLegend: Synonyms Related Words Antonyms | Noun | 1. | A - a metric unit of length equal to one ten billionth of a meter (or 0.0001 micron); used to specify wavelengths of electromagnetic radiation | | 2. |  A - any of several fat-soluble vitamins essential for normal vision; prevents night blindness or inflammation or dryness of the eyesretinol, vitamin A1 - an unsaturated alcohol that occurs in marine fish-liver oils and is synthesized biologically from carotene | | 3. | A - one of the four nucleotides used in building DNA; all four nucleotides have a common phosphate group and a sugar (ribose)nucleotide, base - a phosphoric ester of a nucleoside; the basic structural unit of nucleic acids (DNA or RNA) | | 4. | A - (biochemistry) purine base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNAbiochemistry - the organic chemistry of compounds and processes occurring in organisms; the effort to understand biology within the context of chemistry purine - any of several bases that are derivatives of purine deoxyribonucleic acid, desoxyribonucleic acid, DNA - (biochemistry) a long linear polymer found in the nucleus of a cell and formed from nucleotides and shaped like a double helix; associated with the transmission of genetic information; "DNA is the king of molecules" ribonucleic acid, RNA - (biochemistry) a long linear polymer of nucleotides found in the nucleus but mainly in the cytoplasm of a cell where it is associated with microsomes; it transmits genetic information from DNA to the cytoplasm and controls certain chemical processes in the cell; "ribonucleic acid is the genetic material of some viruses" | | 5. | A - the basic unit of electric current adopted under the Systeme International d'Unites; "a typical household circuit carries 15 to 50 amps"current unit - a measure of the amount of electric charge flowing past a circuit point at a specific time | | 6. |  a - the 1st letter of the Roman alphabetLatin alphabet, Roman alphabet - the alphabet evolved by the ancient Romans which serves for writing most of the languages of western Europe | | 7. |  A - the blood group whose red cells carry the A antigenblood group, blood type - human blood cells (usually just the red blood cells) that have the same antigens |
 Translations A, a [eɪ] n ( letter) → A, a; (MUS): A → la m; A for Andrew (US); A for Able → A de Antonio;
a [ə] indef art [ before vowel or silent h an] → un(a); I haven't got a car → no tengo coche2. (instead of the number "one") → un(a); a year ago → hace un año; a hundred/thousand pounds → cien/mil libras3. ( in expressing ratios, prices etc): 3 a day/week → 3 al día/a la semana; 30p a kilo → 30p el kilo; 3 times a month → 3 veces al mes
 A, a1 [eɪ] n (= letter) → A, a m; (Scol) (= mark); A; (Mus) → la m; A for Andrew, A for Able ( US) → A comme Anatole; A shares npl (Brit) (Stock Exchange) → actions fpl prioritaires
a2 [eɪ, ə] [ an , before vowel and silent h ] indef art 1. un(e); 2. (instead of the number "one") → un(e); a year ago → il y a un an; a hundred/thousand etc pounds → cent/mille etc livres3. (in expressing ratios, prices etc);
 A1, a [eɪ] n ( letter) → A nt, a nt; A for Andrew, A for Able ( US) → A wie Anton; A shares (Brit) (Stock Exchange) → stimmrechtslose Aktien pl
A2 [eɪ] n ( Mus) → A nt, a nt
a [ə] [ an , before vowel and silent h: ] indef art 1. ein; ( before feminine noun) → eine; 2. ( in expressing ratios, prices etc) → pro;
 A, a [eɪ] n ( letter) → A, a f or m inv; (SCOL) (mark) → 10 (ottimo); (MUS): A → la m; A for Andrew (US); A for Able → A come Ancona; from A to Z → dall'A alla Z;
a [ə] ( before vowel or silent h: an) indef art 1. un , uno (+ s impure, gn, pn, ps, x, z) → una f; un' + vowel; 2. (instead of the number "one") → un, una f; 3. ( in expressing ratios, prices etc) → a, per;
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