| aperture, angular | <microscopy> The angle between the most divergent rays that can pass through a lens to form the image of an object. The angle subtended between the axis of a lens and the largest accepted angle of the image-forming rays. With microscope objectives the trigonometric sine of this angle is used to define numerical aperture but as measured from the axial object point. (05 Aug 1998) |
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| artery of angular gyrus | The last branch of the terminal part of the middle cerebral artery distributed to parts of the temporal parietal and occipital lobes. Synonym: arteria gyri angularis, angular artery. (05 Mar 2000) |
| supra-angular | <anatomy> See Surangular. Source: Websters Dictionary (01 Mar 1998) |
| map distance | The degree of separation of two loci on a linkage map, measured in morgans or centimorgans. (05 Mar 2000) |
| genetic distance | <molecular biology> A way of measuring the amount of evolutionary divergence in two separated populations of a species by counting the number of allelic substitutions per locus that have cropped up in each population. (09 Oct 1997) |
| reduced interarch distance | An occluding vertical dimension which results in an excessive interocclusal distance when the mandible is in rest position, and in a reduced interridge distance when the teeth are in contact. (05 Mar 2000) |
| working distance free | <microscopy> The distance between the front lens of the objective and the coverslip (or uncovered object) when the lens is focused on the specimen. (05 Aug 1998) |
| pupillary distance | The distance between the centre of each pupil; the major reference points in measuring for fitting of spectacle frames and lenses. (05 Mar 2000) |
| hyperfocal distance | <microscopy> The nearest distance, h, at which a camera lens focuses the far distance (infinity). This gives the maximum depth of field, the nearest distance in focus is h/2. (05 Aug 1998) |
| small interarch distance | A small distance between the maxillary and mandibular arches. Synonym: close bite. (05 Mar 2000) |
| social distance | The degree of closeness or acceptance an individual or group feels toward another individual or group. (12 Dec 1998) |
| sociometric distance | Some measurable degree of mutual or social perception, acceptance, and understanding; hypothetically, greater sociometric distance is associated with more inaccuracy in evaluating a relationship (e.g., it is easier to understand and deal with a native than a foreigner). (05 Mar 2000) |
| distance | 1. The space between two objects; the length of a line, especially the shortest line joining two points or things that are separate; measure of separation in place. "Every particle attracts every other with a force . . . Inversely proportioned to the square of the distance." (Sir I. Newton) 2. Remoteness of place; a remote place. "Easily managed from a distance." (W. Irving) "'T is distance lends enchantment to the view." (T. Campbell) "[He] waits at distance till he hears from Cato." (Addison) 3. A space marked out in the last part of a race course. "The horse that ran the whole field out of distance." (L'Estrange) In trotting matches under the rules of the American Association, the distance varies with the conditions of the race, being 80 yards in races of mile heaths, best two in three, and 150 yards in races of two-mile heats. at that distance from the winning post in placed the distance post. If any horse has not reached this distance post before the first horse in that heat has reached the winning post, such horse is distanced, and disqualified for cunning again during that race. 4. Relative space, between troops in ranks, measured from front to rear; contrasted with interval, which is measured from right to left. "Distance between companies in close column is twelve yards." 5. Space between two antagonists in fencing. 6. The part of a picture which contains the representation of those objects which are the farthest away, especially. In a landscape. In a picture, the Middle distance is the central portion between the foreground and the distance or the extreme distance. In a perspective drawing, the Point of distance is the point where the visual rays meet. 7. Ideal disjunction; discrepancy; contrariety. 8. Length or interval of time; period, past or future, between two eras or events. "Ten years' distance between one and the other." (Prior) "The writings of Euclid at the distance of two thousand years." (Playfair) 9. The remoteness or reserve which respect requires; hence, respect; ceremoniousness. "I hope your modesty Will know what distance to the crown is due." (Dryden) "'T is by respect and distance that authority is upheld." (Atterbury) 10. A withholding of intimacy; alienation; coldness; disagreement; variance; restraint; reserve. "Setting them [factions] at distance, or at least distrust amongst themselves." (Bacon) "On the part of Heaven, Now alienated, distance and distaste." (Milton) 11. Remoteness in succession or relation; as, the distance between a descendant and his ancestor. 12. The interval between two notes; as, the distance of a fourth or seventh. Angular distance, the distance made at the eye by lines drawn from the eye to two objects. Lunar distance. See Lunar. <astronomy> North polar distance, the arc on the heavens from a heavenly body to the zenith of the observer. It is the complement of the altitude. To keep one's distance, to stand aloof; to refrain from familiarity. "If a man makes keep my distance, the comfort is he keeps his at the same time." (Swift) Origin: F. Distance, L. Distantia. Source: Websters Dictionary (01 Mar 1998) |
| distance ceptor | A nerve mechanism of one of the organs of special sense whereby the subject is brought into relation with his distant environment. (05 Mar 2000) |
| distance of virtual image | <physics> When a simple lens is used as a magnifier for visual observation the eye becomes part of the optical system. A virtual image can be formulated by construction and its apparent distance will vary with the focus of the eye. This will vary among individuals. In a rather arbitrary but standardised assumption, the normal distance for close observation, or reading has been set at 10 inches (250 mm). The optics for the compound microscope have been designed to furnish parallel light from the eyepiece so that the eyes are relaxed for distant viewing. This makes the virtual image lie at infinity. Tests showed that the average observer accommodates somewhat, placing the virtual image rather variably, often about 20 - 25 feet. (05 Aug 1998) |