| pointleted | <botany> Having a small, distinct point; apiculate. Source: Websters Dictionary (01 Mar 1998) |
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| points of convergence | <microscopy> In colour video cameras and monitors, the precise alignment of the images or pictures in the three primary colours (red, green and blue). A lack of convergence gives rise to asymmetrically coloured fringes. (05 Aug 1998) |
| points, conjugate | <microscopy> The pair of points on the principal axis of a mirror or lens so located that light emitted from either point will be focused at the other. Related points in the object and image are located optically so that one is the image of the other. See: polarizing element (05 Aug 1998) |
| Poirier's gland | A lymph node on the uterine artery where it crosses the ureter. (05 Mar 2000) |
| Poirier's line | A line extending from the nasion to the lambda. (05 Mar 2000) |
| Poirier, Paul | <person> French surgeon, 1853-1907. See: Poirier's gland, Poirier's line. (05 Mar 2000) |
| poise | In the CGS system, the unit of viscosity equal to 1 dyne-second per square centimeter and to 0.1 pascal-second. Origin: J. Poiseuille (05 Mar 2000) |
| poiser | <zoology> The balancer of dipterous insects. Source: Websters Dictionary (01 Mar 1998) |
| Poiseuille's law | In laminar flow, the volume of a homogeneous fluid passing per unit time through a capillary tube is directly proportional to the pressure difference between its ends and to the fourth power of its internal radius, and inversely proportional to its length and to the viscosity of the fluid. (05 Mar 2000) |
| Poiseuille's space | The layer of the bloodstream in the capillary vessels, next to the wall of the vessel, that flows slowly and transports the white blood cells along the layer wall, while in the centre the flow is rapid and transports the red blood cells. Synonym: plasma layer, Poiseuille's space, sluggish layer. (05 Mar 2000) |
| Poiseuille's viscosity coefficient | An expression of the viscosity as determined by the capillary tube method; the coefficient η = (πPr4t/8vl), where P is the pressure difference between the inlet and outlet of the tube, r the radius of the tube, l its length, and v the volume of liquid delivered in the time t. If volume is in cm3, time is in seconds, and l and r are in cm, then n will be in poise. (05 Mar 2000) |
| Poiseuille, Jean Leonard Marie | <person> French physiologist and physicist, 1797-1869. See: poise, Poiseuille's viscosity coefficient, Poiseuille's law, Poiseuille's space. (05 Mar 2000) |
| poison | 1. Any agent which, when introduced into the animal organism, is capable of producing a morbid, noxious, or deadly effect upon it; as, morphine is a deadly poison; the poison of pestilential diseases. 2. That which taints or destroys moral purity or health; as, the poison of evil example; the poison of sin. Poison ash. <botany> A poisonous shrub of the genus Rhus (R. Venenata); also called poison ash, poison dogwood, and poison elder. It has pinnate leaves on graceful and slender common petioles, and usually grows in swampy places. Both this plant and the poison ivy (Rhus Toxicodendron) have clusters of smooth greenish white berries, while the red-fruited species of this genus are harmless. The tree (Rhus vernicifera) which yields the celebrated Japan lacquer is almost identical with the poison sumac, and is also very poisonous. The juice of the poison sumac also forms a lacquer similar to that of Japan. Synonym: Venom, virus, bane, pest, malignity. Poison, Venom. Poison usually denotes something received into the system by the mouth, breath, etc. Venom is something discharged from animals and received by means of a wound, as by the bite or sting of serpents, scorpions, etc. Hence, venom specifically implies some malignity of nature or purpose. Origin: F. Poison, in Old French also, a potion, fr. L. Potio a drink, draught, potion, a poisonous draught, fr. Potare to drink. See Potable, and cf. Potion. Source: Websters Dictionary (01 Mar 1998) |
| poison control centres | Facilities which provide information concerning poisons and treatment of poisoning in emergencies. (12 Dec 1998) |
| poison ivy | <botany> A plant that causes a marked allergic (contact) dermatitis in the majority of individuals. (27 Sep 1997) |