| pensive | 1. Thoughtful, sober, or sad; employed in serious reflection; given to, or favorable to, earnest or melancholy musing. "The pensive secrecy of desert cell." (Milton) "Anxious cares the pensive nymph oppressed." (Pope) 2. Expressing or suggesting thoughtfulness with sadness; as, pensive numbers. Origin: F. Pensif, fr. Penser to think, fr. L. Pensare to weigh, ponder, consider, v. Intens. Fr. Pendere to weigh. See Pension, Poise. Source: Websters Dictionary (01 Mar 1998) |
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| penstock | 1. A close conduit or pipe for conducting water, as, to a water wheel, or for emptying a pond, or for domestic uses. 2. The barrel of a wooden pump. Origin: Etymol. Uncertain; perh. Fr. Pen an inclosure + stock. Source: Websters Dictionary (01 Mar 1998) |
| penta- | 1. <prefix> A combining form denoting five; as, pentacapsular; pentagon. 2. <chemistry> Denoting the degree of five, either as regards quality, property, or composition; as, pentasulphide; pentoxide, etc. Also used adjectively. Origin: Gr, a later combining form of five. See Five. (29 Oct 1998) |
| pentabasic | <chemistry> Capable of uniting with five molecules of a monacid base; having five acid hydrogen atoms capable of substitution by a basic radical; said of certain acids. Origin: Penta- + basic. Source: Websters Dictionary (01 Mar 1998) |
| pentacapsular | <botany> Having five capsules. Origin: Penta- + capsular. Source: Websters Dictionary (01 Mar 1998) |
| pentachenium | <botany> A dry fruit composed of five carpels, which are covered by an epigynous calyx and separate at maturity. Origin: NL. See Penta-, and Achenium. Source: Websters Dictionary (01 Mar 1998) |
| pentachloride | <chemistry> A chloride having five atoms of chlorine in each molecule. Origin: Penta- + chloride. Source: Websters Dictionary (01 Mar 1998) |
| pentachlorophenol | <chemical> This toxic chemical is used to kill fungi, weeds, bacteria and algae. (09 Oct 1997) |
| pentachlorophenol hydroxylase | <enzyme> Catalyses the conversion of pcp to 2,3,4,5-tetrachlorohydroquinone in the presence of NADPH and oxygen; flavoprotein from flavobacterium sp. Strain atcc 39723 Registry number: EC 1.14.13.- Synonym: pcp hydroxylase, pcp-4-monooxygenase, pcpb gene product, pentachlorophenol-4-monooxygenase (26 Jun 1999) |
| pentacid | <chemistry> Capable of neutralising, or combining with, five molecules of a monobasic acid; having five hydrogen atoms capable of substitution by acid residues; said of certain complex bases. Origin: Penta- + acid. Source: Websters Dictionary (01 Mar 1998) |
| pentacoccous | <botany> Composed of five united carpels with one seed in each, as certain fruits. See: Penta-, Coccus. Source: Websters Dictionary (01 Mar 1998) |
| pentacrinin | <physiology> A red and purple pigment found in certain crinoids of the genus Pentacrinus. Source: Websters Dictionary (01 Mar 1998) |
| pentacrinite | <zoology> Any species of Pentacrinus. Origin: Penta- + Gr. A lily. Source: Websters Dictionary (01 Mar 1998) |
| pentacrinoid | <zoology> An immature comatula when it is still attached by a stem, and thus resembles a Pentacrinus. Origin: Pentacrinus. Source: Websters Dictionary (01 Mar 1998) |
| pentacrinus | <zoology> A genus of large, stalked crinoids, of which several species occur in deep water among the West Indies and elsewhere. Origin: NL. See Penta-, and Crinum. Source: Websters Dictionary (01 Mar 1998) |