| formazan | <chemical> A water-insoluble coloured azo compound of the general structure, RNH-N==CR'-N==NR', formed by reduction of a tetrazolium salt in the histochemical demonstration of oxidative enzymes Employing this reaction, oxidoreductase activity can be determined quantitatively in tissue sections by allowing the enzymes to act on their specific substrates in the presence of tetrazolium salts. The R's are usually phenyl groups; examples include neotetrazolium, blue tetrazolium, and nitro blue tetrazolium. Pharmacological action: indicators and reagents. (20 Jun 2000) |
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| formboard | <psychology> A board containing cut-outs in various shapes, into which blocks of corresponding shape are to be fitted; a neuropsychological test of which the Tactual Performance Test of the Halstead-Reitan Battery is an example. See: Halstead-Reitan battery. (05 Mar 2000) |
| forme fruste | <biology> A partial, arrested, or inapparent form of disease. Origin: Fr. Unfinished form (05 Mar 2000) |
| formed | 1. <astronomy> Arranged, as stars in a constellation; as, formed stars. 2. <biology> Having structure; capable of growth and development; organised; as, the formed or organised ferments. Formed material, a term employed by Beale to denote the lifeless matter of a cell, that which is physiologically dead, in distinction from the truly germinal or living matter. Source: Websters Dictionary (01 Mar 1998) |
| formed visual hallucination | <psychiatry> Hallucination composed of scenes, often landscapes. (05 Mar 2000) |
| formell | <ornithology> The female of a hawk or falcon. Origin: Dim. Of F. Forme the female of a bird of prey. Source: Websters Dictionary (01 Mar 1998) |
| formic | <chemistry> Pertaining to, or derived from, ants; as, formic acid; in an extended sense, pertaining to, or derived from, formic acid; as, formic ether. Amido formic acid, carbamic acid. Formic acid, a colourless, mobile liquid, HCO.OH, of a sharp, acid taste, occurring naturally in ants, nettles, pine needles, etc, and produced artifically in many ways, as by the oxidation of methyl alcohol, by the reduction of carbonic acid or the destructive distillation of oxalic acid. It is the first member of the fatty acids in the paraffin series, and is homologous with acetic acid. Origin: L. Formica an ant: cf. F. Formique. Source: Websters Dictionary (20 Jun 2000) |
| formic acid | <chemical> The smallest carboxylic acid and a strong caustic, used as an astringent and counterirritant. Structure: HCOOH (05 Mar 2000) |
| formic aldehyde | <chemical> Commonly used fixative and antibacterial agent. As a fixative it is cheap and tends to cause less denaturation of proteins than does glutaraldehyde, particularly if used in a well buffered solution (buffered formalin, formal saline). Old formaldehyde solutions usually contain cross linking contaminants and it is therefore often preferable to used a formaldehyde generating agent such as paraformaldehyde. Formalin fumes, particularly in conjunction with hydrochloric acid vapour, are potently carcinogenic. (20 Jun 2000) |
| formica | <entomology> A Linnaean genus of hymenopterous insects, including the common ants. See: ant. Origin: L, an ant. (30 Mar 1998) |
| formicaroid | <ornithology> Like or pertaining to the family Formicaridae or ant thrushes. Origin: NL. Formicarius, the typical genus. Source: Websters Dictionary (01 Mar 1998) |
| formicary | <entomology> The nest or dwelling of a swarm of ants; an ant-hill. Origin: LL. Formicarium, fr. L. Formica an ant. Source: Websters Dictionary (01 Mar 1998) |
| formicate | <entomology, zoology> Resembling, or pertaining to, an ant or ants. Origin: L. Formica an ant. Source: Websters Dictionary (01 Mar 1998) |
| formication | <symptom> A sensation resembling that made by the creeping of ants on the skin. Origin: L. Formicatio, fr. Formicare to creep like an ant, to feel as if ants were crawling on one's self, fr. Formica ant: cf. F. Formication. Source: Websters Dictionary (01 Mar 1998) |
| formicid | <entomology> Pertaining to the ants. One of the family Formicidae, or ants. Source: Websters Dictionary (01 Mar 1998) |