Part 3135

<h1>Dion\'91a</h1> <Xpage=415>

<hw>Di`o*n\'91"a</hw> <tt>(?)</tt>, <tt>n.</tt> <ety>[NL., fr. Gr. <?/ a name of Aphrodite.]</ety> <fld>(Bot.)</fld> <def>An insectivorous plant. See <er>Venus's flytrap</er>.</def>

<h1>Dionysian</h1> <Xpage=415>

<hw>Di`o*ny"sian</hw> <tt>(?)</tt>, <tt>a.</tt> <def>Relating to Dionysius, a monk of the 6th century; <as>as, the <ex>Dionysian</ex>, or Christian, era</as>.</def>

<cs><col>Dionysian period</col>, <cd>a period of 532 years, depending on the cycle of the sun, or 28 years, and the cycle of the moon, or 19 years; -- sometimes called the <i>Greek paschal cycle<i>, or <i>Victorian period<i>.</cd></cs>

<h1>Diophantine</h1> <Xpage=415>

<hw>Di`o*phan"tine</hw> <tt>(?)</tt>, <tt>a.</tt> <def>Originated or taught by Diophantus, the Greek writer on algebra.</def>

<cs><col>Diophantine analysis</col> <fld>(Alg.)</fld>, <cd>that branch of indeterminate analysis which has for its object the discovery of rational values that satisfy given equations containing squares or cubes; as, for example, to find values of <i>x<i> and <i>y<i> which make <mathex>x<exp>2</exp> + y<exp>2</exp></mathex> an exact square.</cd></cs>

<h1>Diopside</h1> <Xpage=415>

<hw>Di*op"side</hw> <tt>(?)</tt>, <tt>n.</tt> <ety>[Gr. <?/ = <?/ twice + <?/ a sight, fr. the root of <?/ I shall see: cf. F. <ets>diopside</ets>.]</ety> <fld>(Min.)</fld> <def>A crystallized variety of pyroxene, of a clear, grayish green color; mussite.</def>

<h1>Dioptase</h1> <Xpage=415>

<hw>Di*op"tase</hw> <tt>(?)</tt>, <tt>n.</tt> <ety>[Gr. <?/ = <?/ through + <?/ to see: cf. F. <ets>dioptase</ets>.]</ety> <fld>(Min.)</fld> <def>A hydrous silicate of copper, occurring in emerald-green crystals.</def>

<h1>Diopter, Dioptra</h1> <Xpage=415>

<hw><hw>Di*op"ter</hw> <tt>(?)</tt>, <hw>Di*op"tra</hw> <tt>(?)</tt>,<hw> <tt>n.</tt> <ety>[L. <ets>dioptra</ets>, fr. Gr. <?/. See 2d <er>Dioptric</er>.]</ety> <def>An optical instrument, invented by Hipparchus, for taking altitudes, leveling, etc.</def>

<h1>Dioptre</h1> <Xpage=415>

<hw>Di*op"tre</hw> <tt>(?)</tt>, <tt>n.</tt> <ety>[F. See 2d <er>Dioptric</er>.]</ety> <fld>(Optics)</fld> <def>A unit employed by oculists in numbering glasses according to the metric system; a refractive power equal to that of a glass whose principal focal distance is one meter.</def>

<h1>Dioptric</h1> <Xpage=415>

<hw>Di*op"tric</hw> <tt>(?)</tt>, <tt>a.</tt> <fld>(Optics)</fld> <def>Of or pertaining to the dioptre, or to the metric system of numbering glasses.</def> -- <def2><tt>n.</tt> <def>A dioptre. See <er>Dioptre</er>.</def></def2>

<h1>Dioptric, Dioptrical</h1> <Xpage=415>

<hw><hw>Di*op"tric</hw> <tt>(?)</tt>, <hw>Di*op"tric*al</hw> <tt>(?)</tt>,<hw> <tt>a.</tt> <ety>[Gr. <?/ belonging to the use of the <?/; <?/ = <?/ through + the root of <?/ I shall see: cf. F. <ets>dioptrique</ets>.]</ety> <def>Of or pertaining to dioptrics; assisting vision by means of the refraction of light; refractive; <as>as, the <ex>dioptric</ex> system; a <ex>dioptric</ex> glass or telescope.</as></def> "<i>Dioptrical</i> principles."

<i>Nichol.</i>

<cs><col>Dioptric curve</col> <fld>(Geom.)</fld>, <cd>a Cartesian oval. See under <er>Cartesian</er>.</cd></cs>

<h1>Dioptrics</h1> <Xpage=415>

<hw>Di*op"trics</hw> <tt>(?)</tt>, <tt>n.</tt> <ety>[Gr. <?/ <?/: cf. F. <ets>dioptrique</ets>.]</ety> <fld>(Optics)</fld> <def>The science of the refraction of light; that part of geometrical optics which treats of the laws of the refraction of light in passing from one medium into another, or through different mediums, as air, water, or glass, and esp. through different lenses; -- distinguished from <i>catoptrics</i>, which refers to <i>reflected</i> light.</def>

<h1>Dioptry</h1> <Xpage=415>

<hw>Di*op"try</hw> <tt>(?)</tt>, <tt>n.</tt> <fld>(Optics)</fld> <def>A dioptre.</def>

<h1>Diorama</h1> <Xpage=415>

<hw>Di`o*ra"ma</hw> <tt>(?)</tt>, <tt>n.</tt> <ety>[Gr. <?/ to see through; <?/ = <?/ through + <?/ to see; cf. <?/ that which is seen, a sight: cf. F. <ets>diorama</ets>. Cf. <er>Panorama</er>.]</ety>