perceptual masking |
The interference of one perceptual stimulus with another causing a decrease or lessening in perceptual effectiveness.
(12 Dec 1998) |
percesoces |
<zoology> An order of fishes including the gray mullets (Mugil), the barracudas, the silversides, and other related fishes. So called from their relation both to perches and to pikes.
Origin: NL, fr. L. Perca a perch + esox, -ocis, a pike.
Source: Websters Dictionary
(01 Mar 1998) |
perch |
<zoology>
1. Any fresh water fish of the genus Perca and of several other allied genera of the family Percidae, as the common American or yellow perch (Perca flavescens, or Americana), and the European perch (P. Fluviatilis).
2. Any one of numerous species of spiny-finned fishes belonging to the Percidae, Serranidae, and related families, and resembling, more or less, the true perches. Black perch. The black bass. The flasher. The sea bass. Blue perch, the cunner. Gray perch, the fresh water drum. Red perch, the rosefish. Red-bellied perch, the long-eared pondfish. Perch pest, a small crustacean, parasitic in the mouth of the perch. Silver perch, the yellowtail. Stone, or Striped, perch, the pope. White perch, the Roccus, or Morone, Americanus, a small silvery serranoid market fish of the Atlantic coast.
Origin: OE. Perche, F. Perche, L. Perca, fr. Gr.; cf. Dark-coloured, Skr. Pni spotted, speckled, and E. Freckle.
Source: Websters Dictionary
(01 Mar 1998) |
perched wetland |
<ecology> Wetlands away from stream or river influence with water made available by general drainage.
(09 Oct 1997) |
perchlorate |
<chemistry> A salt of perchloric acid.
Source: Websters Dictionary
(01 Mar 1998) |
perchloric |
<chemistry> Pertaining to, or designating, the highest oxygen acid (HClO4), of chlorine.
Synonym: hyperchloric.
Origin: Pref. Per- + chloric.
Source: Websters Dictionary
(01 Mar 1998) |
perchloric acid |
<chemical> An oxidizing agent that is used in analytical chemistry for separation of potassium from sodium.
Chemical name: Perchloric acid
(12 Dec 1998) |
perchloride |
<chemistry> A chloride having a higher proportion of chlorine than any other chloride of the same substance or series.
Source: Websters Dictionary
(01 Mar 1998) |
perchromic |
<chemistry> Pertaining to, or designating, a certain one of the highly oxidized compounds of chromium, which has a deep blue colour, and is produced by the action of hydrogen peroxide.
Origin: Pref. Per- + chromic.
Source: Websters Dictionary
(01 Mar 1998) |
perciform |
<zoology> Pertaining to the Perciformes.
Origin: NL, & L. Perca a perch.
Source: Websters Dictionary
(01 Mar 1998) |
perciformes |
<zoology> An extensive tribe or suborder of fishes, including the true perches (Percidae); the pondfishes (Centrarchidae); the sciaenoids (Sciaenidae); the sparoids (Sparidae); the serranoids (Serranidae), and some other related families.
Source: Websters Dictionary
(01 Mar 1998) |
perclose |
1. Same as Parclose.
2. Conclusion; end.
Origin: OF. Parclose an inclosed place; L. Per through + claudere, clausum, to shut.
Source: Websters Dictionary
(01 Mar 1998) |
percoid |
<zoology> Belonging to, or resembling, the perches, or family Percidae.
Any fish of the genus Perca, or allied genera of the family Percidae.
Origin: L. Perca a perch: cf. F. Percoide.
Source: Websters Dictionary
(01 Mar 1998) |
percoidea |
<zoology> Same as Perciformes.
Source: Websters Dictionary
(01 Mar 1998) |
percolation |
The act or process of percolating, or filtering; filtration; straining.
<pharmacology> Specifically, the process of exhausting the virtues of a powdered drug by letting a liquid filter slowly through it.
Origin: L. Percolatio.
Source: Websters Dictionary
(01 Mar 1998) |
