| pearl-ash | <chemistry> A white amorphous or granular substance which consists principally of potassium carbonate, and has a strong alkaline reaction. The hydroxide of potassium hydrate, a hard white brittle substance, KOH, having strong caustic and alkaline properties; hence The impure potassium carbonate obtained by leaching wood ashes, and evaporating the lye, or as a white crystalline pearl-ash. It has previously been an important source of potassium compounds, and previously used in making soap, glass, etc. Synonym: caustic potash. Source: Websters Dictionary (01 Mar 1998) |
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| pearl-worker's disease | Inflammatory hypertrophy of the bones affecting grinders of mother-of-pearl. (05 Mar 2000) |
| pearlfish | <zoology> Any fish whose scales yield a pearl-like pigment used in manufacturing artificial pearls, as the bleak, and whitebait. Source: Websters Dictionary (01 Mar 1998) |
| pearlstone | <chemical> A glassy volcanic rock of a grayish colour and pearly luster, often having a spherulitic concretionary structure due to the curved cracks produced by contraction in cooling. Source: Websters Dictionary (01 Mar 1998) |
| pearlwort | <botany> A name given to several species of Sagina, low and inconspicuous herbs of the Chickweed family. Source: Websters Dictionary (01 Mar 1998) |
| pearmain | <botany> The name of several kinds of apples; as, the blue pearmain, winter pearmain, and red pearmain. Source: Websters Dictionary (01 Mar 1998) |
| Pearson, Karl | <person> English mathematician, 1857-1936. See: Poisson-Pearson formula, McArdle-Schmid-Pearson disease. (05 Mar 2000) |
| peas | A variable annual leguminous vine (pisum sativum) that is cultivated for its rounded smooth or wrinkled edible protein-rich seeds, the seed of the pea, and the immature pods with their included seeds. (12 Dec 1998) |
| peastone | <chemical> Pisolite. Source: Websters Dictionary (01 Mar 1998) |
| peasweep | <zoology> The pewit, or lapwing. The greenfinch. Origin: So called from its note. Source: Websters Dictionary (01 Mar 1998) |
| peat | 1. <chemical> A piece of turf cut for use as a fuel. 2. <botany> A mass of partially carbonised plant tissue formed by partial decomposition in water of various plants and especially. Of mosses of the genus Sphagnum, widely found in many parts of the world, varying in consistency from a turf to a slime used as a fertiliser, as stable litter, as a fuel, and for making charcoal. (09 Oct 1997) |
| peat moss | A highly absorbent moss used as a substitute for absorbent cotton or gauze in surgical dressing and sanitary napkins. Synonym: muskeag moss, peat moss. (05 Mar 2000) |
| peau d'orange | A swollen pitted skin surface overlying carcinoma of the breast in which there is both stromal infiltration and lymphatic obstruction with oedema. Origin: Fr. Orange peel (05 Mar 2000) |
| peba | <zoology> An armadillo (Tatusia novemcincta) which is found from Texas to Paraguay. Synonym: tatouhou. Origin: Cf. Pg. Peba. Source: Websters Dictionary (01 Mar 1998) |
| pebble | 1. A small roundish stone or bowlder; especially, a stone worn and rounded by the action of water; a pebblestone. "The pebbles on the hungry beach." "As children gathering pebbles on the shore." (Milton) 2. Transparent and colourless rock crystal; as, Brazilian pebble; so called by opticians. Pebble powder, slow-burning gunpowder, in large cubical grains. Scotch pebble, varieties of quartz, as agate, chalcedony, etc, obtained from cavities in amygdaloid. Origin: AS. Papolstan; cf. L. Papula pimple, mote. See Stone. Source: Websters Dictionary (01 Mar 1998) |