Part 3857

<cs><col>Epicyclic train</col> <fld>(Mach.)</fld>, <cd>a train of mechanism in which epicyclic motion is involved; esp., a train of spur wheels, bevel wheels, or belt pulleys, in which an arm, carrying one or more of the wheels, sweeps around a center lying in an axis common to the other wheels.</cd></cs>

<h1>Epicycloid</h1> <Xpage=501>

<hw>Ep`i*cy"cloid</hw> <tt>(?)</tt>, <tt>n.</tt> <ety>[<ets>Epicycle</ets> + <ets>-oid</ets>: cf. F. <ets>\'82picyclo\'8bde</ets>.]</ety> <fld>(Geom.)</fld> <def>A curve traced by a point in the circumference of a circle which rolls on the convex side of a fixed circle.</def>

<note>&hand; Any point rigidly connected with the rolling circle, but not in its circumference, traces a curve called an <i>epitrochoid</i>. The curve traced by a point in the circumference of the rolling circle when it rolls on the concave side of a fixed circle is called a <i>hypocycloid</i>; the curve traced by a point rigidly connected with the rolling circle in this case, but not its circumference, is called a <i>hypotrochoid</i>. All the curves mentioned above belong to the class class called <i>roulettes</i> or <i>trochoids</i>. See <er>Trochoid</er>.</note>

<h1>Epicycloidal</h1> <Xpage=501>

<hw>Ep`i*cy*cloid"al</hw> <tt>(?)</tt>, <tt>a.</tt> <def>Pertaining to the epicycloid, or having its properties.</def>

<cs><col>Epicycloidal wheel</col>, <cd>a device for producing straight-line motion from circular motion, on the principle that a pin fastened in the periphery of a gear wheel will describe a straight line when the wheel rolls around inside a fixed internal gear of twice its diameter.</cd></cs>

<h1>Epideictic</h1> <Xpage=501>

<hw>Ep`i*deic"tic</hw> <tt>(?)</tt>, <tt>a.</tt> <ety>[Gr. <?/, fr. <?/ to show forth, display; <?/ + <?/ to show. Cf. <er>Epidictic</er>.]</ety> <def>Serving to show forth, explain, or exhibit; -- applied by the Greeks to a kind of oratory, which, by full amplification, seeks to persuade.</def>

<h1>Epidemic, Epidemical</h1> <Xpage=501>

<hw><hw>Ep`i*dem"ic</hw> <tt>(?)</tt>, <hw>Ep`i*dem"ic*al</hw> <tt>(?)</tt>,<hw> <tt>a.</tt> <ety>[L. <ets>epidemus</ets>, Gr. <?/, <?/, among the people, epidemic; <?/ in + <?/ people: cf. F. <ets>\'82pid\'82mique</ets>. Cf. <er>Demagogue</er>.]</ety>

<p><b>1.</b> <fld>(Med.)</fld> <def>Common to, or affecting at the same time, a large number in a community; -- applied to a disease which, spreading widely, attacks many persons at the same time; <as>as, an <ex>epidemic</ex> disease; an <ex>epidemic</ex> catarrh, fever, etc.</as> See <er>Endemic</er>.</def>

<p><b>2.</b> <def>Spreading widely, or generally prevailing; affecting great numbers, as an epidemic does; <as>as, <ex>epidemic</ex> rage; an <ex>epidemic</ex> evil.</as></def>

<blockquote>It was the <b>epidemical</b> sin of the nation. <i>Bp. Burnet.</i></blockquote>

<h1>Epidemic</h1> <Xpage=501>

<hw>Ep`i*dem"ic</hw> <tt>(?)</tt>, <tt>n.</tt> <ety>[Cf. <er>Epidemy</er>.]</ety>

<p><b>1.</b> <fld>(Med.)</fld> <def>An epidemic disease.</def>

<p><b>2.</b> <def>Anything which takes possession of the minds of people as an epidemic does of their bodies; <as>as, an <ex>epidemic</ex> of terror</as>.</def>

<h1>Epidemically</h1> <Xpage=501>

<hw>Ep`i*dem"ic*al*ly</hw>, <tt>adv.</tt> <def>In an epidemic manner.</def>

<h1>Epidemiography</h1> <Xpage=501>

<hw>Ep`i*de`mi*og"ra*phy</hw> <tt>(?)</tt>, <tt>n.</tt> <ety>[<ets>Epidemy</ets> + <ets>-graphy</ets>.]</ety> <fld>(Med.)</fld> <def>A treatise upon, or history of, epidemic diseases.</def>

<h1>Epidemiological</h1> <Xpage=501>

<hw>Ep`i*de`mi*o*log"ic*al</hw> <tt>(?)</tt>, <tt>a.</tt> <def>Connected with, or pertaining to, epidemiology.</def>

<h1>Epidemiologist</h1> <Xpage=501>

<hw>Ep`i*de`mi*ol"o*gist</hw> <tt>(?)</tt>, <tt>n.</tt> <def>A person skilled in epidemiology.</def>

<h1>Epidemiology</h1> <Xpage=501>

<hw>Ep`i*de`mi*ol"o*gy</hw> <tt>(?)</tt>, <tt>n.</tt> <ety>[<ets>Epidemy</ets> + <ets>-logy</ets>.]</ety> <fld>(Med.)</fld> <def>That branch of science which treats of epidemics.</def>