| parabiotic | Relating to, or characterised by, parabiosis. (05 Mar 2000) |
|---|---|
| parabiotic flap | A skin flap bridging from one animal to another. (05 Mar 2000) |
| parablast | <biology> A portion of the mesoblast (of peripheral origin) of the developing embryo, the cells of which are especially concerned in forming the first blood and blood vessels. Origin: Cf. Gr. To grow beside. See Para-, and -blast. Source: Websters Dictionary (01 Mar 1998) |
| parablastic | <biology> Of or pertaining to the parablast; as, the parablastic cells. Source: Websters Dictionary (01 Mar 1998) |
| parabola | Origin: NL, fr. Gr.; so called because its axis is parallel to the side of the cone. See Parable, and cf. Parabole. <geometry> A kind of curve; one of the conic sections formed by the intersection of the surface of a cone with a plane parallel to one of its sides. It is a curve, any point of which is equally distant from a fixed point, called the focus, and a fixed straight line, called the directrix. See Focus. One of a group of curves defined by the equation y = ax^n where n is a positive whole number or a positive fraction. For the cubical parabola n = 3; for the semicubical parabola n = 3/2. See Cubical, and Semicubical. The parabolas have infinite branches, but no rectilineal asymptotes. Source: Websters Dictionary (01 Mar 1998) |
| parabolical | 1. Of the nature of a parable; expressed by a parable or figure; allegorical; as, parabolical instruction. 2. [From Parabola. <geometry> Having the form or nature of a parabola; pertaining to, or resembling, a parabola; as, a parabolic curve. Generated by the revolution of a parabola, or by a line that moves on a parabola as a directing curve; as, a parabolic conoid. Parabolic conoid, a paraboloid; a conoid whose directing curve is a parabola. See Conoid. <optics> Parabolic mirror, a mirror having a paraboloidal surface which gives for parallel rays (as those from very distant objects) images free from aberration. It is used in reflecting telescopes. Parabolic spindle, the solid generated by revolving the portion of a parabola cut off by a line drawn at right angles to the axis of the curve, about that line as an axis. Parabolic spiral, a spiral curve conceived to be formed by the periphery of a semiparabola when its axis is wrapped about a circle; also, any other spiral curve having an analogy to the parabola. Origin: Gr. Figurative: cf. F. Parabolique. See Parable. Source: Websters Dictionary (01 Mar 1998) |
| parabolism | <mathematics> The division of the terms of an equation by a known quantity that is involved in the first term. Origin: From Parabola. Source: Websters Dictionary (01 Mar 1998) |
| paraboloid | <geometry> The solid generated by the rotation of a parabola about its axis; any surface of the second order whose sections by planes parallel to a given line are parabolas. The term paraboloid has sometimes been applied also to the parabolas of the higher orders. Origin: Parabola: cf. F. Paraboloide. Source: Websters Dictionary (01 Mar 1998) |
| paraboloid condenser | A type of dark-field condenser. (05 Mar 2000) |
| paraboloid dark field condenser | <microscopy> A lens of parabolic shape. The vertex end is ground back so that its focus can be brought into coincidence with the specimen on the slide. A central stop is provided to block the central rays. It is used chiefly for medium- power work. (05 Aug 1998) |
| parabrachial nuclei | The cell groups flanking the brachium conjunctivum at levels immediately caudal to the inferior colliculus; they serve as way-stations in the pathways ascending from the nucleus of solitary tract to the thalamus and hypothalamus, and receive afferent fibres from the hypothalamus and amygdaloid body. Synonym: nuclei parabrachiales. (05 Mar 2000) |
| parabronchium | Origin: NL. See Para-, Bronchia. <anatomy> One of the branches of an ectobronchium or entobronchium. Source: Websters Dictionary (01 Mar 1998) |
| parabulia | Perversion of volition or will in which one impulse is checked and replaced by another. Origin: para-+ G. Boule, will (05 Mar 2000) |
| paracanthoma | <tumour> A neoplasm arising from abnormal hyperplasia of the prickle cell layer of the skin. Origin: para-+ G. Akantha, a thorn, + -oma, tumour (05 Mar 2000) |
| paracanthosis | 1. The development of paracanthomas. 2. A division of tumours that includes the cutaneous epitheliomas. (05 Mar 2000) |