Part 536

<cs><col>Aplanatic focus</col> of a lens <fld>(Opt.)</fld>, <cd>the point or focus from which rays diverging pass the lens without spherical aberration. In certain forms of lenses there are two such foci; and it is by taking advantage of this fact that the best aplanatic object glasses of microscopes are constructed.</cd></cs>

<h1>Aplanatism</h1> <Xpage=68>

<hw>A*plan"a*tism</hw> <tt>(#)</tt>, <tt>n.</tt> <def>Freedom from spherical aberration.</def>

<h1>Aplastic</h1> <Xpage=68>

<hw>A*plas"tic</hw> <tt>(#)</tt>, <tt>a.</tt> <ety>[Pref. <ets>a-</ets> not + <ets>plastic</ets>.]</ety> <def>Not plastic or easily molded.</def>

<h1>Aplomb</h1> <Xpage=68>

<hw>A`plomb"</hw> <tt>(#)</tt>, <tt>n.</tt> <ety>[F., lit. perpendicularity; <?/ to + <ets>plomb</ets> lead. See <er>Plumb</er>.]</ety> <def>Assurance of manner or of action; self-possession.</def>

<h1>Aplotomy</h1> <Xpage=68>

<hw>A*plot"o*my</hw> <tt>(#)</tt>, <tt>n.</tt> <ety>[Gr. <?/ simple + <?/ a cutting.]</ety> <fld>(Surg.)</fld> <def>Simple incision.</def>

<i>Dunglison.</i>

<h1>Aplustre</h1> <Xpage=68>

<hw>A*plus"tre</hw> <tt>(#)</tt>, <tt>n.</tt> <ety>[L., fr. Gr. <?/.]</ety> <fld>(Rom. Antiq.)</fld> <def>An ornamental appendage of wood at the ship's stern, usually spreading like a fan and curved like a bird's feather.</def>

<i>Audsley.</i>

<h1>Aplysia</h1> <Xpage=68>

<hw>A*plys"i*a</hw> <tt>(#)</tt>, <tt>n.</tt> <ety>[Gr. <?/ a dirty sponge, fr. <?/ unwashed; <?/ priv. + <?/ to wash.]</ety> <fld>(Zo\'94l.)</fld> <def>A genus of marine mollusks of the order <spn>Tectibranchiata</spn>; the sea hare. Some of the species when disturbed throw out a deep purple liquor, which colors the water to some distance. See <i>Illust</i>. in Appendix.</def>

<h1>Apneumona</h1> <Xpage=68>

<hw>Ap*neu"mo*na</hw> <tt>(#)</tt>, <tt>n. pl.</tt> <ety>[NL., fr. Gr. <?/ priv. + <?/, <?/, a lung.]</ety> <fld>(Zo\'94l.)</fld> <def>An order of holothurians in which the internal respiratory organs are wanting; -- called also <spn>Apoda</spn> or <spn>Apodes</spn>.</def>

<h1>Apn</a</h1> <Xpage=68>

<hw>Ap*n<?/"a</hw> <tt>(#)</tt>, <tt>n.</tt> <ety>[NL., fr. Gr. <?/ priv. + <?/, <?/, breath, <?/ to breathe, blow.]</ety> <fld>(Med.)</fld> <def>Partial privation or suspension of breath; suffocation.</def>

<h1>Apo</h1> <Xpage=68>

<hw>Ap"o</hw> <tt>(#)</tt>. <ety>[Gr. <?/. See <er>Ab-</er>.]</ety> <def>A prefix from a Greek preposition. It usually signifies <i>from</i>, <i>away from</i>, <i>off</i>, or <i>asunder</i>, <i>separate</i>; <as>as, in <ex>apo</ex>cope (a cutting <ex>off</ex>), <ex>apo</ex>state, <ex>apo</ex>stle (one sent <ex>away</ex>), <ex>apo</ex>carpous</as>.</def>

<h1>Apocalypse</h1> <Xpage=68>

<hw>A*poc"a*lypse</hw> <tt>(#)</tt>, <tt>n.</tt> <ety>[L. <ets>apocalypsis</ets>, Gr. <?/, fr. <?/ to uncover, to disclose; <?/ from + <?/ to cover, conceal: cf. F. <ets>apocalypse</ets>.]</ety> <p><b>1.</b> <def>The revelation delivered to St. John, in the isle of Patmos, near the close of the first century, forming the last book of the New Testament.</def>

<p><b>2.</b> <def>Anything viewed as a revelation; as disclosure.</def>

<blockquote>The new <b>apocalypse</b> of Nature. <i>Carlyle.</i></blockquote>

<h1>Apocalyptic, Apocalyptical</h1> <Xpage=68>

<hw><hw>A*poc`a*lyp"tic</hw> <tt>(#)</tt>, <hw>A*poc`a*lyp"tic*al</hw> <tt>(#)</tt>,<hw> <tt>a.</tt> <ety>[Gr. <?/.]</ety> <def>Of or pertaining to a revelation, or, specifically, to the Revelation of St. John; containing, or of the nature of, a prophetic revelation.</def>

<cs><col>Apocolyptic number</col>, <cd>the number 666, mentioned in <i>Rev. xiii. 18</i>. It has been variously interpreted.</cd></cs>