A paronychia is an infection of the skin that surrounds a toenail or fingernail. Acute paronychia â This usually appears as a sudden, very painful area of swelling, warmth and redness around a fingernail or toenail, usually after an injury to the area.
Definition of 'reflector'. reflector (rÉªflektÉÊ³ ) A reflector is a small piece of specially patterned glass or plastic which is fitted to the back of a bicycle or car or to a post beside the road, and which glows when light shines on it. A reflector is a type of telescope which uses a mirror that is shaped like a ball.
Circular paraboloid. A parabolic (or paraboloid or paraboloidal) reflector (or dish or mirror) is a reflective surface used to collect or project energy such as light, sound, or radio waves. Its shape is part of a circular paraboloid, that is, the surface generated by a parabola revolving around its axis. The parabolic reflector transforms an incoming plane wave traveling along the axis into a spherical wave converging toward the focus.