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Comprehensive
Dictionary Suite
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aberration an imperfection in an optical lens, or the blurring caused by such an imperfection. [1/3 definitions]
aperture an opening, often adjustable, that controls the amount of light reaching the lens on a camera or other optical instrument. [1/2 definitions]
bar code a set of vertical bars of varying widths containing coded information that can be read by an optical scanner, usu. printed on the labels of consumer goods, on mail, and the like. (Cf. Universal Product Code.)
binocular (usu. pl.) a magnifying optical instrument used with both eyes at once, such as field glasses or opera glasses. [1/2 definitions]
CD1 abbreviation of "compact disk," a palm-sized disk on which music, data, or the like has been digitally encoded, that is read by laser and transmitted to a playback device; optical disk.
collimate to accurately adjust the line of sight of (an optical instrument such as a telescope). [1/2 definitions]
cross hairs the two fine hairs, wires, or the like, one vertical and the other horizontal, that cross at right angles in an optical instrument such as a gunsight and that aid the viewer in aiming or focusing accurately.
crown glass a very clear optical glass with low refraction. [1/2 definitions]
diaphragm a disklike device that moves to regulate the amount of light entering an optical instrument such as a camera. [1/5 definitions]
digital versatile disc an optical storage format for digital data, resembling a compact disc but with greater storage capacity; digital video disc; DVD.
digital video disc an optical storage format for digital data, or the physical disc that the data is stored on, resembling a compact disc but with greater storage capacity; DVD. [1/2 definitions]
endoscope a long, slender, tubular optical instrument inserted into an inner, hollow body part, such as the lungs or bowel, esp. for examination, diagnosis, or surgical treatment.
eyepiece the lens or lenses in an optical instrument, such as a microscope or telescope, through which one views the object or image under scrutiny.
flint glass a bright fusible optical glass that contains lead oxide and is used for lenses and crystal.
focal length the distance between the optical center of a lens or curved mirror and the far distant point where light rays converge upon an object.
focus the point at which rays, esp. optical, come together, or from which they seem to radiate. [4/9 definitions]
Fresnel lens a thin and relatively flat optical lens made of many stepped concentric rings, and having the properties of a thicker, more concave lens.
germanium a tetravalent metal chemical element that has thirty-two protons in each nucleus and occurs naturally as a contaminant of coal, but can be purified for use in transistors and as a component of high-quality optical glass. (symbol: Ge)
goniometer an optical instrument that measures angles, esp. in crystals or other solids. [1/2 definitions]
interferometer a device used to make precise measurements of wavelengths using acoustic, optical, or microwave interference phenomena.
laser disk see "optical disk."