<B>prothoracic, </B>adjective.<DL COMPACT><DD> of or having to do with the prothorax. <BR> <I>Ex. the prothoracic cavity, a prothoracic gland.</I> </DL>
<A NAME="prothorax">
<B>prothorax, </B>noun, pl. <B>-thoraxes,</B> <B>-thoraces.</B><DL COMPACT><DD> the anterior division of an insect's thorax, bearing the first pair of legs. </DL>
<A NAME="prothrombase">
<B>prothrombase, </B>noun.<DL COMPACT><DD> the proenzyme of thrombase. </DL>
<A NAME="prothrombin">
<B>prothrombin, </B>noun.<DL COMPACT><DD> a substance in the blood plasma, essential to clotting, from which thrombin is derived; thrombogen. </DL>
<A NAME="protist">
<B>protist, </B>noun, pl. <B>protists,</B> <B>protista.</B><DL COMPACT><DD> any one of the group of organisms that includes all one-celled animals and plants, such as the bacteria, protozoans, and yeasts. <BR> <I>Ex. Plantlike protists probably appeared several times through symbiotic unions between free-living, autotrophic prokaryote blue-green algae and various heterotrophic eukaryote protists (Scientific American).</I> </DL>
<A NAME="protistan">
<B>protistan, </B>adjective, noun.<DL COMPACT><DD><I>adj. </I> of or having to do with protists. <DD><I>noun </I> a single-celled organism; protist. </DL>
<B>protistology, </B>noun.<DL COMPACT><DD> the study of protists. <BR> <I>Ex. "The Protistan Kingdom: Protists and Viruses" [is] a nontechnical introduction to protistology: bacteria, ciliated cells, amebas, sporozoans, bacteriophages, and contagious germs (Science News).</I> </DL>
<A NAME="protium">
<B>protium, </B>noun.<DL COMPACT><DD> the ordinary isotope of hydrogen, having a mass number of 1.0 </DL>
<A NAME="proto">
<B>proto-,</B><DL COMPACT><DD> (combining form.) <DD><B> 1. </B>first in time, as in <BR> <I>Ex. prototype.</I> <DD><B> 2. </B>first in importance; chief; primary, as in <BR> <I>Ex. protoplasm.</I> <DD> Also, <B>prot-</B> before vowels. </DL>
<A NAME="protoactinium">
<B>protoactinium, </B>noun.<DL COMPACT><DD> the former name of protactinium. </DL>
<A NAME="protoanthropic">
<B>protoanthropic, </B>adjective.<DL COMPACT><DD> of or belonging to the earliest period of the existence of man. </DL>
<A NAME="protobiont">
<B>protobiont, </B>noun.<DL COMPACT><DD> an elementary or primordial organism. <BR> <I>Ex. As a preliminary stage in the total process of organicevolution, chemical evolution of course reaches its climax when lifeless organic molecules are assembled by chance into a living organism. This first form of life is what the Russian biochemist A. I. Oparin calls a "protobiont" (Scientific American).</I> </DL>
<A NAME="protobioticsoup">
<B>protobiotic soup, =primordial soup.</B></DL>
<A NAME="protocanonical">
<B>protocanonical, </B>adjective.<DL COMPACT><DD> of or forming a first or original canon. </DL>
<A NAME="protocanonicalbooks">
<B>protocanonical books,</B><DL COMPACT><DD> the books of the Bible whose canonicity has always been universally acknowledged in the church. </DL>
<A NAME="protocatechuicacid">
<B>protocatechuic acid,</B><DL COMPACT><DD> a crystalline compound derived from vanillin or produced synthetically, occurring naturally in various plants. </DL>
<A NAME="protoceras">
<B>protoceras, </B>noun.<DL COMPACT><DD> an extinct ungulate mammal of North America, about the size of a sheep and distantly related to the chevrotains, with two or three pairs of horns on the head of the male. </DL>
<A NAME="protoceratops">
<B>protoceratops, </B>noun.<DL COMPACT><DD> a species of hornless, plant-eating dinosaur, about six feet long, that lived during the late Cretaceous period in Asia and North America. </DL>
<A NAME="protocol">
<B>protocol, </B>noun, verb, <B>-colled,</B> <B>-colling.</B><DL COMPACT><DD><I>noun </I> <B>1. </B>the rules of etiquette of the diplomatic corps. <DD><B> 2. </B>rules for any procedure. <DD><B> 3. </B>a first draft or record from which a document, especially a treaty, is prepared. <DD><B> 4. </B>a formal or official statement of a proceeding or transaction, such as a clinical report, or a report on a scientific experiment or on the preparation and testing of a drug. <DD><B> 5. </B>set procedures that permit communication between two or more computer systems. <BR> <I>Ex. He points out that the asynchronous protocol used by most personal-computer communications packages has a higher potential of interference errors than synchronous ... protocols (Personal Computing).</I> <DD><B> 6. </B>(U.S.) the original record of a Spanish land grant made in parts of the Southwest and West. <DD><I>v.i. </I> to draw up protocols. <DD><I>v.t. </I> to embody in a protocol. </DL>
<B>protocolary, </B>adjective.<DL COMPACT><DD> of or having to do with protocol or a protocol. <BR> <I>Ex. After these protocolary preliminaries, I got down to the main purpose of my visit (New Yorker).</I> </DL>
<B>protoctist, </B>noun.<DL COMPACT><DD> any member of a kingdom of organisms that comprises the protists of earlier classification and certain multicellular organisms, such as kelp. </DL>
<A NAME="protoderm">
<B>protoderm, </B>noun. <B>=dermatogen.</B></DL>
<A NAME="protodynastic">
<B>protodynastic, </B>adjective.<DL COMPACT><DD> of or having to do with the earliest royal dynasties of a country. </DL>
<A NAME="protofascism">
<B>protofascism, </B>noun.<DL COMPACT><DD> a movement or ideology characterized by fascist tendencies and ideas and usually associated with a political party of the far right. </DL>
<A NAME="protofascist">
<B>protofascist, </B>noun, adjective.<DL COMPACT><DD><I>noun </I> <B>1. </B>a member of a protofascist party. <DD><B> 2. </B>a person who favors or supports protofascism. <DD><I>adj. </I> of or having to do with protofascism or protofascists. <BR> <I>Ex. ... the protofascist wing of the Syrian political spectrum (Dwight J. Simpson).</I> </DL>
<A NAME="protogalaxy">
<B>protogalaxy, </B>noun, pl. <B>-axies.</B><DL COMPACT><DD><B> 1. </B>a hypothetical mass of contracting gas in space from which the galaxies may have formed as the result of a cosmic explosion of hydrogen. <DD><B> 2. </B>a galaxy in the process of formation, before any stars have formed in it. <BR> <I>Ex. A protogalaxy consisting of an irregular cloud of gas and probably some dust, with a mass of a little less than a million times that of the sun, existed in intergalactic space somewhat more than 10 billion years ago (Scientific American).</I> </DL>
<A NAME="protogermanic">
<B>Proto-Germanic, </B>adjective, noun.<DL COMPACT><DD><I>adj. </I> of or having to do with the hypothetical language that was the ancestor of the Germanic languages. <DD><I>noun </I> this language. </DL>
<A NAME="protogine">
<B>protogine, </B>noun.<DL COMPACT><DD> a fine-grained variety of granite, occurring chiefly in the Alps. </DL>
<B>protohistoric, </B>adjective.<DL COMPACT><DD> of or belonging to the beginnings of recorded history. </DL>
<A NAME="protohistory">
<B>protohistory, </B>noun.<DL COMPACT><DD> history at the dawn or beginnings of recorded history; protohistoric matters or times. </DL>
<A NAME="protohuman">
<B>protohuman, </B>adjective.<DL COMPACT><DD> resembling or preceding the earliest human; prehominid. </DL>
<A NAME="protoindoeuropean">
<B>Proto-Indo-European, </B>noun.<DL COMPACT><DD> the hypothetical prehistoric language that was the ancestor of the Indo-European languages. </DL>
<A NAME="protolanguage">
<B>protolanguage, </B>noun.<DL COMPACT><DD> a hypothetical, reconstructed language assumed to be the ancestor of one or more recorded or existing languages. </DL>
<A NAME="protolithic">
<B>protolithic, </B>adjective.<DL COMPACT><DD> of or having to do with the earliest Stone Age; eolithic. </DL>
<A NAME="protomartyr">
<B>protomartyr, </B>noun.<DL COMPACT><DD><B> 1. </B>the first martyr in any cause. <DD><B> 2. </B>Stephen, the first Christian martyr (in the Bible, Acts 7). </DL>
<B>proton, </B>noun.<DL COMPACT><DD> a tiny particle carrying one unit of positive electricity. All atoms are built up of electrons and protons. The number of protons in an atom is the atomic number of the element. A proton has a mass about 1,836 times that of an electron. </DL>
<A NAME="protonaccelerator">
<B>proton accelerator,</B><DL COMPACT><DD> a device, such as a bevatron, for increasing the velocity of protons and other atomic particles, thereby increasing their energy. </DL>
<A NAME="protonate">
<B>protonate, </B>transitive verb, <B>-ated,</B> <B>-ating.</B><DL COMPACT><DD> (Chemistry.) to provide with a proton; add a proton to. </DL>
<A NAME="protonation">
<B>protonation, </B>noun.<DL COMPACT><DD> (Chemistry.) the addition of a proton. <BR> <I>Ex. The hydride complexes are usually obtained by reduction or protonation of suitable metal complexes. All the positively charged species listed in Table I were obtained by protonation, usually in very strong acid (Science).</I> </DL>
<A NAME="protonbeam">
<B>proton beam,</B><DL COMPACT><DD> a beam of high-energy protons as developed by a proton accelerator. </DL>
<A NAME="protondecay">
<B>proton decay,</B><DL COMPACT><DD> the radioactive transmutation of one chemical element into another by the emission of a proton from an unstable nucleus. <BR> <I>Ex. Proton decay ... is a process in which a nucleus emits a proton and decreases both atomic number and atomic weight by one (Science News).</I> </DL>
<A NAME="protonema">
<B>protonema, </B>noun, pl. <B>-mata.</B><DL COMPACT><DD> a filamentous structure in mosses from which the more visible, leafy portion grows. </DL>
<A NAME="protonemal">
<B>protonemal, </B>adjective.<DL COMPACT><DD> of or having to do with a protonema. </DL>
<A NAME="protonic">
<B>protonic, </B>adjective.<DL COMPACT><DD> of or having to do with a proton or protons. </DL>
<A NAME="protonotary">
<B>protonotary, </B>noun, pl. <B>-taries.</B> <B>=prothonotary.</B></DL>
