| angular acceleration | The rate of change of angular velocity; e.g., when a centrifuge rotor is speeding up, or when there is a simultaneous change in velocity and direction, as in an aircraft in a tight spin. (05 Mar 2000) |
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| acceleration | The act of accelerating, or the state of being accelerated; increase of motion or action; as, a falling body moves toward the earth with an acceleration of velocity; opposed to retardation. "A period of social improvement, or of intellectual advancement, contains within itself a principle of acceleration." (I. <astronomy> Taylor) Acceleration of the moon, the increase of the moon's mean motion in its orbit, in consequence of which its period of revolution is now shorter than in ancient times. Acceleration and retardation of the tides. See Priming of the tides, under Priming. Diurnal acceleration of the fixed stars, the amount by which their apparent diurnal motion exceeds that of the sun, in consequence of which they daily come to the meridian of any place about three minutes fifty-six seconds of solar time earlier than on the day preceding. Acceleration of the planets, the increasing velocity of their motion, in proceeding from the apogee to the perigee of their orbits. Origin: L. Acceleratio: cf. F. Acceleration. Source: Websters Dictionary (01 Mar 1998) |
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| acceleration phase | <cell biology, cell culture> A period of increasing growth before the log phase in a culture of microbes. After the culture is started on a medium, at first there is no growth (the lag phase) and then the microbes start to gradually grow (acceleration phase) until they reach a constant maximum rate of growth (log phase). (15 Jan 1998) |
| radial acceleration | The centripetal acceleration of a particle or vehicle moving along a curved path at a constant velocity; e.g., turning a curve in an automobile, pulling out of a dive, or performing a loop manoeuvre in an aircraft. In aviation, acceleration varies directly with the square of the air speed and inversely with the radius of the turn (a = V2/r, where V is air speed and r is radius of turn). (05 Mar 2000) |
| linear acceleration | The rate of change of velocity without a change in direction; e.g., when the speed of an aircraft increases while flying a straight pathway. (05 Mar 2000) |
| angular | 1. Relating to an angle or to angles; having an angle or angles; forming an angle or corner; sharp-cornered; pointed; as, an angular figure. 2. Measured by an angle; as, angular distance. 3. Lean; lank; raw-boned; ungraceful; sharp and stiff in character; as, remarkably angular in his habits and appearance; an angular female. Angular aperture, Angular distance. See Aperture, Distance. Angular motion, the motion of a body about a fixed point or fixed axis, as of a planet or pendulum. It is equal to the angle passed over at the point or axis by a line drawn to the body. Angular point, the point at which the sides of the angle meet; the vertex. Angular velocity, the ratio of anuglar motion to the time employed in describing. Origin: L. Angularis, fr. Angulus angle, corner. See Angle. <anatomy> A bone in the base of the lower jaw of many birds, reptiles, and fishes. Source: Websters Dictionary (01 Mar 1998) |
| angular aldehyde | The aldehyde group attached to carbon 13 (between rings C and D) of the steroid nucleus in aldosterone. (05 Mar 2000) |
| angular aperture | The angle, in air, of light that passes from the object to the ends of the diameter of the front lens of the microscope objective. (05 Mar 2000) |
| angular artery | <anatomy, artery> The terminal branch of the facial artery; distribution, muscles and skin of side of nose; anastomoses, lateral nasal, and dorsal artery of nose and palpebrals from the ophthalmic artery, thereby providing an external-internal carotid arterial anastomosis. Synonym: artery of angular gyrus. Synonym: arteria angularis. (05 Mar 2000) |
| angular cheilitis | Inflammation and fissuring radiating from the commissures of the mouth secondary to predisposing factors such as lost vertical dimension in denture wearers, nutritional deficiencies, atopic dermatitis, or Candida albicans infection. Synonym: angular stomatitis, commissural cheilitis, perleche. (05 Mar 2000) |
| angular conjunctivitis | A subacute bilateral conjunctival inflammation sometimes caused by the Moraxella bacillus, marked by redness of the lateral canthi and scanty, stringy discharge that adheres to the lashes. Synonym: Moraxella conjunctivitis. (05 Mar 2000) |
| angular convolution | angular gyrus |
| angular curvature | A gibbous deformity, i.e., a sharp angulation of the spine, occurring in Pott's disease. Synonym: Pott's curvature. (05 Mar 2000) |
| angular methyl | A methyl group attached to carbon 10 (between rings A and B) or to carbon 13 (between rings C and D) of the steroid nucleus. (05 Mar 2000) |
| angular momentum | <physics> Momentum involved in the rotation of a body about an axis, conserved as is ordinary momentum (see momentum). Angular momentum is defined as the cross product of ordinary momentum with the position vector running from the axis of rotation to the body whose angular momentum is being determined. Torque is the rate of change of angular momentum with time. (12 Nov 1997) |
| angular notch | A sharp angular depression in the lesser curvature of the stomach at the junction of the body with the pyloric canal. Synonym: incisura angularis, sulcus angularis. (05 Mar 2000) |