<B>ionosonde, </B>noun.<DL COMPACT><DD> an instrument for studying the ionosphere. </DL>
<A NAME="ionosphere">
<B>ionosphere, </B>noun.<DL COMPACT><DD> the region of the atmosphere between the stratosphere and the exosphere. It begins about 50 miles above the earth and ends at an altitude of about 300 miles. The ionosphere is composed of layers of air ionized by solar ultraviolet radiation that reflect certain radio waves, making transmission over long distances on earth possible. </DL>
<A NAME="ionospheric">
<B>ionospheric, </B>adjective.<DL COMPACT><DD> in or having to do with the ionosphere. adv. <B>ionospherically.</B> </DL>
<A NAME="ionpropulsion">
<B>ion propulsion,</B><DL COMPACT><DD> an experimental method of propelling space vehicles by the ejection of beams of ions. The propulsion system includes an energy source such as a nuclear reactor, a heat exchanger, or a generator, an ion source such as cesium, and an ejection device. </DL>
<A NAME="ionpump">
<B>ion pump,</B><DL COMPACT><DD> a device for producing a vacuum by ionizing gas molecules and then collecting them with the aid of an electric field. <BR> <I>Ex. In spite of the many advantages of the diffusion pump, it is often replaced in small laboratory systems by the ion pump (Scientific American).</I> </DL>
<A NAME="ionrocket">
<B>ion rocket,</B><DL COMPACT><DD> a rocket propelled by ion propulsion. </DL>
<A NAME="iontophoresis">
<B>iontophoresis, </B>noun.<DL COMPACT><DD> a method of injecting ionized drugs or other substances by the use of a direct current and two electrodes attached to the body. </DL>
<A NAME="iontophoretic">
<B>iontophoretic, </B>adjective.<DL COMPACT><DD> of or having to do with iontophoresis. </DL>
<A NAME="ioof">
<B>I.O.O.F.,</B><DL COMPACT><DD> Independent Order of Odd Fellows. </DL>
<A NAME="iorw">
<B>I.O.R.W.,</B><DL COMPACT><DD> Improved Order of Red Men. </DL>
<A NAME="iota">
<B>iota, </B>noun.<DL COMPACT><DD><B> 1. </B>a very small part or quantity; bit; jot. <BR> <I>Ex. There is not an iota of truth in his story. I utter these words without the least iota of doubt in my own mind (James T. Farrell).</I> (SYN) particle, whit, mite. <DD><B> 2. </B>the ninth letter of the Greek alphabet. </DL>
<A NAME="iotacism">
<B>iotacism, </B>noun.<DL COMPACT><DD><B> 1. </B>excessive use or repetition of the letter iota (or <I>I</I>) or of its sound. <DD><B> 2. </B>the pronunciation of other Greek vowels like iota (as <I>I</I> in <I>machine</I>), as in modern Greek. </DL>
<A NAME="iou">
<B>I.O.U.</B> or <B>I O U</B> (no periods),<DL COMPACT><DD><B> 1. </B>I owe you. <DD><B> 2. </B>an informal note showing a debt. <BR> <I>Ex. Write me an IOU for ten dollars and I'll give you ten dollars. Joe collected on more than 30 of the many I.O.U.s he holds (Time).</I> </DL>
<A NAME="iow">
<B>I.O.W.,</B><DL COMPACT><DD> Isle of Wight. </DL>
<A NAME="iowa">
<B>Iowa, </B>noun, pl. <B>-wa</B> or <B>-was.</B><DL COMPACT><DD><B> 1. </B>a member of a small Indian tribe of the Plains region of the United States. <DD><B> 2. </B>the Siouan language of this tribe. </DL>
<A NAME="iowan">
<B>Iowan, </B>adjective, noun.<DL COMPACT><DD><I>adj. </I> of or having to do with Iowa. <DD><I>noun </I> a native or inhabitant of Iowa. </DL>
<A NAME="ipa">
<B>IPA</B> (no periods) or <B>I.P.A.,</B><DL COMPACT><DD><B> 1. </B>International Phonetic Alphabet. <DD><B> 2. </B>International Phonetic Association. </DL>
<A NAME="ipecac">
<B>ipecac, </B>noun.<DL COMPACT><DD><B> 1. </B>a medicine made from the dried roots and rhizomes of a South American shrub, used chiefly as an emetic and expectorant. <DD><B> 2. </B>the dried roots and rhizomes. <DD><B> 3. </B>the shrub. It belongs to the madder family. </DL>
<A NAME="ipecacuanha">
<B>ipecacuanha, </B>noun. <B>=ipecac.</B></DL>
<A NAME="iphigenia">
<B>Iphigenia, </B>noun.<DL COMPACT><DD> (Greek Legend.) the daughter of Agamemnon and Clytemnestra. Her father intended to sacrifice her to Artemis to obtain favorable winds for the Greek ships sailing to Troy, but Artemis put a hart in her place and carried Iphigenia to Tauris to become her priestess. </DL>
<A NAME="ipo">
<B>IPO</B> (no periods),<DL COMPACT><DD> initial public offering. </DL>
<A NAME="ipomoea">
<B>ipomoea, </B>noun.<DL COMPACT><DD><B> 1. </B>any one of a group of largely twining or creeping plants of the morning-glory family, including the sweet potato, morning-glory, and many tropical American varieties used medicinally as cathartics. <DD><B> 2. </B>the dried root of one of these plants, from which a cathartic resin is obtained. </DL>
<A NAME="ippf">
<B>IPPF</B> (no periods),<DL COMPACT><DD> International Planned Parenthood Federation. </DL>
<A NAME="iproniazid">
<B>iproniazid, </B>noun.<DL COMPACT><DD> a drug prepared from isoniazid, formerly used in the treatment of tuberculosis but now primarily used in the treatment of mental depression. </DL>
<A NAME="ips">
<B>ips</B> or <B>IPS</B> (no periods),<DL COMPACT><DD> inches per second. </DL>
<A NAME="ipsa">
<B>IPSA</B> (no periods),<DL COMPACT><DD> International Political Science Association. </DL>
<A NAME="ipsedixit">
<B>ipse dixit,</B><DL COMPACT><DD> a dogmatic assertion; opinion based merely on someone's authority. <BR> <I>Ex. Mr. Moore assures us that he has given us all that any reasonable reader could require; but one cannot be satisfied with an editor's ipse dixit (Listener).</I> </DL>
<A NAME="ipsilateral">
<B>ipsilateral, </B>adjective.<DL COMPACT><DD> that is on the same side. <BR> <I>Ex. The response ... was significantly larger for contralateral than for ipsilateral stimulation (Stone and Taylor).</I> adv. <B>ipsilaterally.</B> </DL>
<A NAME="ipsissimaverba">
<B>ipsissima verba,</B><DL COMPACT><DD> (Latin.) the very same words; word for word. </DL>
<A NAME="ipsofacto">
<B>ipso facto,</B><DL COMPACT><DD> (Latin.) by that very fact; by the fact itself. <BR> <I>Ex. Any economic function that has persisted so long, ipso facto will surely continue far into the distant future (Sales Management).</I> </DL>
<A NAME="ipsojure">
<B>ipso jure,</B><DL COMPACT><DD> (Latin.) by the law itself. </DL>
<A NAME="ipswichsparrow">
<B>Ipswich sparrow,</B><DL COMPACT><DD> a large, pale-brownish sparrow with a streaked breast, that nests on Sable Island, Nova Scotia. </DL>
<A NAME="ipts">
<B>IPTS</B> (no periods),<DL COMPACT><DD> International Practical Temperature Scale (the temperature scale in common scientific and industrial use, expressed in terms of the centigrade (Celsius) scale). </DL>
<A NAME="ipu">
<B>I.P.U.</B> or <B>IPU</B> (no periods),<DL COMPACT><DD> Inter-Parliamentary Union (an organization of members of parliaments and other legislative bodies, formed in 1888 to promote the peaceful settlement of international disputes). </DL>
<A NAME="iq">
<B>i.q.,</B><DL COMPACT><DD> the same as (Latin, <I>idem quod</I>). </DL>
<A NAME="iq">
<B>IQ</B> (no periods) or <B>I.Q.,</B><DL COMPACT><DD> intelligence quotient. <BR> <I>Ex. Overambitious parents frequently pressure their children beyond their IQ capacities in the effort to get them into prestige colleges (Wall Street Journal).</I> </DL>
<A NAME="iqal">
<B>iqal, </B>noun.<DL COMPACT><DD> the thick band of twisted chord that keeps the Arab headdress or kaffiyeh in place. </DL>
<A NAME="iqsy">
<B>IQSY</B> (no periods) or <B>I.Q.S.Y.,</B><DL COMPACT><DD> International Quiet Sun Year. </DL>
<A NAME="ir">
<B>ir-</B> (1),<DL COMPACT><DD> (prefix.) the form of <B>in-</B> (1) (not) before <I>r,</I> as in <I>irrational, irregular, irresistible.</I> </DL>
<A NAME="ir">
<B>ir-</B> (2),<DL COMPACT><DD> (prefix.) the form of <B>in-</B> (2) (in) before <I>r,</I> as in <I>irrigate.</I> </DL>
<A NAME="ir">
<B>Ir</B> (no period),<DL COMPACT><DD> iridium (chemical element). </DL>
<B>IRA</B> (1) (no periods) or <B>I.R.A.</B> (1),<DL COMPACT><DD> Irish Republican Army (an association of Irish nationalists outlawed in 1931 that continues to operate, often by sabotage and other means, for a united Ireland to include the Irish Republic and Northern Ireland). </DL>
<A NAME="ira">
<B>IRA</B> (2) (no periods),<DL COMPACT><DD> International Reading Association. </DL>
<A NAME="ira">
<B>IRA</B> (3) (no periods) or <B>I.R.A.</B> (2),<DL COMPACT><DD> Individual Retirement Account (a pension fund, into which a person deposits wages and defers paying tax on them or on the interest until withdrawals begin). IRA's are administered by banks, savings and loan associations, insurance companies, etc. The money in an IRA earns interest that is added to the account. <BR> <I>Ex. Keogh ... retirement accounts ... are in many ways similar to IRAs but are available only to the self-employed (Chicago Tribune).</I> </DL>
<A NAME="iracund">
<B>iracund, </B>adjective.<DL COMPACT><DD> easily made angry; irascible. </DL>
<A NAME="iracundity">
<B>iracundity, </B>noun.<DL COMPACT><DD> readiness to become angry; irascibility. </DL>
<A NAME="irade">
<B>irade, </B>noun.<DL COMPACT><DD> a decree of the former Sultan of Turkey or other Moslem ruler. </DL>
<A NAME="irafurorbrevisest">
<B>ira furor brevis est,</B><DL COMPACT><DD> (Latin.) anger is a brief insanity. </DL>
<A NAME="iran">
<B>Iran.,</B><DL COMPACT><DD> Iranian. </DL>
<A NAME="irani">
<B>Irani, </B>adjective. <B>=Iranian.</B></DL>
<A NAME="iranian">
<B>Iranian, </B>adjective, noun.<DL COMPACT><DD><I>adj. </I> of or having to do with Iran, its people, or their language; Persian. <DD><I>noun </I> <B>1. </B>a person born or living in Iran, especially one speaking an Iranian language; Persian. <DD><B> 2. </B>the language of Iran; Persian. <DD><B> 3. </B>the branch of Indo-European languages that includes Old Persian and Avestan. </DL>
