a. [ L. acidus sour, fr. the root ak to be sharp: cf. F. acide. Cf. Acute. ] 1. Sour, sharp, or biting to the taste; tart; having the taste of vinegar: as, acid fruits or liquors. Also fig.: Sour-tempered. [ 1913 Webster ]

He was stern and his face as acid as ever. A. Trollope. [ 1913 Webster ]

2. Of or pertaining to an acid; as, acid reaction. [ 1913 Webster ]

n. 1. A sour substance. [ 1913 Webster ]

2. (Chem.) One of a class of compounds, generally but not always distinguished by their sour taste, solubility in water, and reddening of vegetable blue or violet colors. They are also characterized by the power of destroying the distinctive properties of alkalies or bases, combining with them to form salts, at the same time losing their own peculiar properties. They all contain hydrogen, united with a more negative element or radical, either alone, or more generally with oxygen, and take their names from this negative element or radical. Those which contain no oxygen are sometimes called hydracids in distinction from the others which are called oxygen acids or oxacids. [ 1913 Webster ]

☞ In certain cases, sulphur, selenium, or tellurium may take the place of oxygen, and the corresponding compounds are called respectively sulphur acids or sulphacids, selenium acids, or tellurium acids. When the hydrogen of an acid is replaced by a positive element or radical, a salt is formed, and hence acids are sometimes named as salts of hydrogen; as hydrogen nitrate for nitric acid, hydrogen sulphate for sulphuric acid, etc. In the old chemistry the name acid was applied to the oxides of the negative or nonmetallic elements, now sometimes called anhydrides. [ 1913 Webster ]

adj. 1. yielding an acid in aqueous solution [ WordNet 1.5 ]

a. (Min.) 1. Containing a high percentage of silica; -- opposed to basic. [ 1913 Webster ]

2. of or relating to acid; having the character of an acid, as an acidic solution. [ PJC ]

a. [ L. acidus sour + -ferous. ] Containing or yielding an acid. [ 1913 Webster ]

a. Capable of being acidified, or converted into an acid. [ 1913 Webster ]

a. Producing acidity; converting into an acid. Dana. [ 1913 Webster ]

n. [ Cf. F. acidification. ] The act or process of acidifying, or changing into an acid. [ 1913 Webster ]

n. (Chem.) A simple or compound principle, whose presence is necessary to produce acidity, as oxygen, chlorine, bromine, iodine, etc. [ 1913 Webster ]

v. t. [ imp. & p. p. Acidified p. pr. & vb. n. Acidifying ] [ L. acidus sour, acid + -fy: cf. F. acidifier. ] 1. To make acid; to convert into an acid; as, to acidify sugar. [ 1913 Webster ]

2. To sour; to imbitter. [ 1913 Webster ]

His thin existence all acidified into rage. Carlyle. [ 1913 Webster ]

n. [ L. acidus acid + -meter. ] (Chem.) An instrument for ascertaining the strength of acids. Ure. [ 1913 Webster ]

n. [ L. acidus acid + -metry. ] (Chem.) The measurement of the strength of acids, especially by a chemical process based on the law of chemical combinations, or the fact that, to produce a complete reaction, a certain definite weight of reagent is required. -- Ac`id*i*met"ric*al a. [1913 Webster]

n. [ L. acidites, fr. acidus: cf. F. acidité. See Acid. ] The quality of being sour; sourness; tartness; sharpness to the taste; as, the acidity of lemon juice. [ 1913 Webster ]

adj. 1. thriving in a relatively acid environment; -- especially of plants requiring a pH well below 7 alkaline-loving [ WordNet 1.5 ]

adv. Sourly; tartly. [ 1913 Webster ]

n. Acidity; sourness. [ 1913 Webster ]

adj. 1. 1 growing well in an acid medium; said of some bacteria
Syn. -- aciduric [ WordNet 1.5 ]

n. 1. abnormally high acidity of the blood and other body fluids. [ WordNet 1.5 ]

adj. 1. of or pertaining to acidosis; suffering from acidosis. [ WordNet 1.5 ]

. (Iron Metal.) That variety of either the Bessemer or the open-hearth process in which the converter or hearth is lined with acid, that is, highly siliceous, material. Opposed to basic process. [ Webster 1913 Suppl. ]

v. t. [ imp. & p. p. Acidulated p. pr. & vb. n. Acidulating ] [ Cf. F. aciduler. See Acidulous. ] To make sour or acid in a moderate degree; to sour somewhat. Arbuthnot. [ 1913 Webster ]

adj. 1. made slightly acidic [ WordNet 1.5 ]

a. Having an acid quality; sour; acidulous. “With anxious, acidulent face.” Carlyle. [ 1913 Webster ]

a. [ L. acidulus, dim. of acidus. See Acid. ] Slightly sour; sub-acid; sourish; as, an acidulous tincture. E. Burke. [ 1913 Webster ]

Acidulous mineral waters, such as contain carbonic anhydride. [ 1913 Webster ]

v. 1. to wash (blue jeans) in acid, so as to cause the color to fade. [ WordNet 1.5 ]

an aliphatic dicarboxylic acid (HO.CO.(CH2)4.CO.OH), containing six carbon atoms in a linear chain. It is found in beet juice. It is used in the manufacture of synthetic plastics such as Nylon, as well as other products. [ PJC ]

n. (Chem.) An organic acid (C6H5.CH(OH).COOH) extracted from bitter almonds; called also mandelic acid and α-Hydroxybenzeneacetic acid. [ PJC ]

‖ n. [ Pref. anti- + acid. ] (Med.) A remedy for neutralizing acidity, especially of the stomach, as an alkali or absorbent. -- a. Counteractive of acidity. [ 1913 Webster + AS ]

(Chem.) A white, crystalline substance, CH2(CO.NH)2.CO, derived from alloxantin, also from malonic acid and urea, and regarded as a substituted urea. [ 1913 Webster ]

a. [ Pref. bi- + acid. ] (Chem.) Having two hydrogen atoms which can be replaced by negative atoms or radicals to form salts; -- said of bases. See Diacid. [ 1913 Webster ]

n. [ L. carbo coal + oleum oil. ] (Chem.) same as phenol{ 1 }, (C6H5.OH). See phenol{ 1 }.
Syn. -- phenol{ 1 }, hydroxybenzene, phenyl hydroxide, phenic acid. [ PJC ]

n. (Chem.) an organic compound whose acidity is due to the presence of a carboxyl gorup. Monocarboxylic acids (such as acetic acid or butyric acid) have one carboxyl group, dicarboxylic acids (such as oxalic acid or malonic acid) have two, tricarboxylic acids (such as citric acid) have three. [ PJC ]

n. any freshwater fish of the family Characinidae; -- also called characin.
Syn. -- characin, characin fish. [ WordNet 1.5 ]

n. a natural family of tropical freshwater fishes of Africa and southern and central America.
Syn. -- family Characidae. [ WordNet 1.5 ]

(Chem.), an organic acid, C3O3N3H3, first obtained by heating uric acid or urea, and called pyrouric acid; afterwards obtained from isocyanic acid. It is a white crystalline substance, odorless and almost tasteless; -- called also tricarbimide. [ 1913 Webster ]

n. a nucleic acid, usually of very high molecular weight, consisting of a linear sequence of monomer units of deoxyribonucleotides, occurring in most organisms in pairs of strands, wound together in the form of a double helix; it is the main component of chromosomes and contains the genetic information which is the basis of heredity, transmitted from parent to progeny, and found in all living organisms except for certain viruses which have RNA as their basic genetic material; -- usually referred to by the acronym DNA.
Syn. -- DNA, desoxyribonucleic acid. [ PJC ]

☞ The monomer units making up the DNA each contain one of four heterocyclic bases: thymine, adenine, cytosine, or guanine. The genetic information is contained in the precise sequence of these monomer units, which ultimately specify the sequence of proteins to be made by the organism's biosynthetic processes, mediated through the synthesis of RNA having a base sequence corresponding to that of the DNA. The DNA sequence also specifies the sequence of the various RNA molecules the RNA base sequence being a copy of that on one of the DNA strands. Most of the RNA synthesized is involved in protein synthesis. In the double-helical form of DNA, the thymine on one strand is paired with the adenine on the opposite strand, and cytosine of one strand is paired with guanine on the opposite strand. There is in DNA also certain controlling information concerning the timing and amount of RNA to be made, encoded within the sequence of the DNA in ways that are still being elucidated.
When this structure is replicated in the course of cell multiplication, two identical double-helical molecules are formed, each containing one strand from the original molecule. Each resulting molecule is distributred to either the parent or progeny organism, and this is the basic mechanism for transmission of hereditary information. In RNA-based viruses, or those having single strands of DNA (as certain viruses), the genetic information transmission occurs through a double-stranded intermediate by a similar mechanism.
In some organisms slight modifications of the bases of DNA are found, such as methylcytosine or, in some viruses, uracil or hydroxymethyluracil; these unusual bases act analogously to the normal bases in their genetic coding function. A small percentage of methylcytosine is found in many organisms, and it serves in some cases as a special signal, as for restriction enzymes. [ PJC ]

n. same as deoxyribonucleic acid. [ Rare ] [ PJC ]

n. same as deoxyribonucleic acid. [ PJC ]

a. [ Pref. di- + acid. ] (Chem.) Divalent; -- said of a base or radical as capable of saturating two acid monad radicals or a dibasic acid. Cf. Dibasic, a., and Biacid. [ 1913 Webster ]

v. t. To free from acid. [ 1913 Webster ]

a. [ L. fracidus mellow, soft. ] Rotten from being too ripe; overripe. [ Obs. ] Blount. [ 1913 Webster ]

n. (Chem.), A plant growth hormone of the gibberellin series (C19H22O6), also called gibberellin A₃. It was first isolated from the fungus Gibberella fujikuroi. It is used to promote the growth of seedlings. See also gibberellin. MI11 [ PJC ]

a. [ Hex- + acid. ] (Chem.) Having six atoms or radicals capable of being replaced by acids; hexatomic; hexavalent; -- said of bases; as, mannite is a hexacid base. [ 1913 Webster ]

n. [ Hydr- + acid: cf. F. hydracide. ] (Chem.) An acid containing hydrogen; -- sometimes applied to distinguish acids like hydrochloric, hydrofluoric, and the like, which contain no oxygen, from the oxygen acids or oxacids. See Acid. [ 1913 Webster ]

n. (Chem., Bot.) A plant hormone (C10H9NO2) recognized as the principle growth regulator in higher plants; called also heteroauxin. Abbreviated IAA. Chemically it is 1H-indole-3-acetic acid. [ PJC ]

n. (Chem.) The unsaturated dicarboxylic acid CH2=C(COOH)CH2.COOH, also called methylenesuccynic acid and propylene dicarboxylic acid. [ PJC ]

(Chem.), a white, crystalline substance, CH3.(CH2)10.COOH, resembling palmitic acid, and obtained from the fruit of the bay tree, and various other vegetable sources. The sodium salt (sodium lauryl sulfate) is used as a detergent. Syn. -- dodecanoic acid, laurostearic acid, dodecoic acid. [ 1913 Webster + PJC ]

n. (Chem.) An unsaturated dicarboxylic acid (HO.CO.CH=CH.CO.OH) of cis conformation, having various uses in the manufacture of artificial resins, the dyeing and finishing of wool, silk, and cotton, and also combined with certain drugs to make salts more soluble than the basic forms. The corresponding isomer having trans conformation, is identical in chemical formula, is called fumaric acid. MI11 [ PJC ]

n. A dibasic acid H2MnO4, formed from manganese, analogous to sulphuric acid; it is found only in solution and in manganate salts. [ 1913 Webster + WordNet 1.5 ]

a. [ Mon- + acid. ] (Chem.) Having one hydrogen atom replaceable by an acidic atom or radical.
Syn. -- monoacid, monoacidic, monacidic. [ 1913 Webster ]

2. Capable of neutralizing one equivalent of a monobasic acid; -- said of bases, and of certain metals. [ 1913 Webster ]