<B>nucleophile, </B>noun.<DL COMPACT><DD> a substance that is strongly attracted to atomic nuclei. </DL>
<A NAME="nucleophilic">
<B>nucleophilic, </B>adjective.<DL COMPACT><DD> strongly attracted to the nuclei of atoms. <BR> <I>Ex. nucleophilic ions or molecules.</I> </DL>
<A NAME="nucleoplasm">
<B>nucleoplasm, </B>noun.<DL COMPACT><DD> the protoplasm found in the nucleus of a cell, not including the nucleoli; karyoplasm. </DL>
<A NAME="nucleoplasmic">
<B>nucleoplasmic, </B>adjective.<DL COMPACT><DD><B> 1. </B>having to do with nucleoplasm. <DD><B> 2. </B>like nucleoplasm. </DL>
<A NAME="nucleoprotein">
<B>nucleoprotein, </B>noun.<DL COMPACT><DD> any one of a group of substances present in the nuclei of cells and viruses, consisting of proteins in combination with nucleic acids. On hydrolysis, nucleoproteins yield purine or pyrimidine bases, phosphoric acid, and a pentose sugar. </DL>
<A NAME="nucleoside">
<B>nucleoside, </B>noun.<DL COMPACT><DD> any one of a group of compounds of a nitrogen base (purine or pyrimidine) and a sugar (pentose), similar to a nucleotide but lacking phosphoric acid. Adenosine is a nucleoside. </DL>
<A NAME="nucleosomal">
<B>nucleosomal, </B>adjective.<DL COMPACT><DD> of or having to do with a nucleosome or nucleosomes. </DL>
<A NAME="nucleosome">
<B>nucleosome, </B>noun.<DL COMPACT><DD> the basic structural unit of chromatin. <BR> <I>Ex. Each nucleosome is roughly spherical, about 100 A (10 nm) in diameter, and consists of 8 histone molecules and about 200 pairs of DNA (Bruce A. J. Ponder). The discovery of the nucleosome was a great advance in understanding chromosome structure (Eugene R. Katz).</I> </DL>
<A NAME="nucleosynthesis">
<B>nucleosynthesis, </B>noun.<DL COMPACT><DD> the process by which chemical elements are created from the nuclei of hydrogen. </DL>
<A NAME="nucleotidase">
<B>nucleotidase, </B>noun.<DL COMPACT><DD> an enzyme which splits phosphoric acid from a nucleotide, producing a nucleoside. </DL>
<A NAME="nucleotide">
<B>nucleotide, </B>noun.<DL COMPACT><DD> any one of a group of compounds of sugar, phosphoric acid, and a purine or pyrimidine base. Nucleotides are the principal constituents of nucleic acid and determine the structure of genes. <BR> <I>Ex. Inert molecules known as nucleotides and found in DNA were used as the starting material (Science News Letter).</I> </DL>
<A NAME="nucleus">
<B>nucleus, </B>noun, pl. <B>-clei</B> or <B>-cleuses.</B><DL COMPACT><DD><B> 1. </B>a central part or thing around which other parts or things are collected. <BR> <I>Ex. A very strange old gentleman, whose eccentricity had become the nucleus for a thousand fantastic stories (Hawthorne). The few hundred families, which formed the original nucleus of her citizenship (Charles Merivale).</I> (SYN) center, core, heart. <DD><B> 2. </B>(Figurative.) a beginning to which additions are to be made. <BR> <I>Ex. His five-dollar bill became the nucleus of a flourishing bank account. He had the nucleus of a good plan, but it required working out.</I> <DD><B> 3. </B>a proton, or a group of protons and neutrons, or other nuclear particles, forming the central part of an atom. A nucleus has a positive charge of electricity. The nucleus forms the core around which the electrons orbit. It also contains most of the mass of the whole atom. <BR> <I>Ex. The exact ratio of protons to neutrons in a stable nucleus depends on the total number of particles it contains (J. Little).</I> <DD><B> 4. </B>the fundamental, stable arrangement of atoms in a particular compound, to which other atoms may be joined in various ways. <DD><B> 5. </B>(Biology.) a mass of specialized protoplasm found in most plant and animal cells, without which the cell cannot grow and divide. A nucleus is different in structure from the rest of the cell. It consists of complex arrangements of proteins, nucleic acids, and lipids surrounded by a delicate membrane, and typically containing such structures as chromosomes and nucleoli. The nucleus controls growth, cell division, and other activities, and contains DNA, a nucleic acid which passes on the genetic characteristics of the cell. <BR> <I>Ex. The hereditary endowment of a plant or animal is now known to be determined by a very special kind of material found primarily in the threadlike chromosomes that may be seen under the microscope in the nucleus of the cell (Atlantic).</I> <DD><B> 6. </B>the relatively dense, central part of a galaxy or of a comet's head. <BR> <I>Ex. The astronomers tell us that some of these comets have no visible nucleuses (James Fenimore Cooper).</I> <DD><B> 7. </B>one of a number of anatomically distinct masses of gray matter in the brain or spinal cord of vertebrates, consisting of the cell bodies of nerve cells, having special functions, and connected to one another by nerve fibers. <DD><B> 8. </B>(Meteorology.) a speck of dust or other particle upon which water vapor condenses, as to form a drop; condensation nucleus. <DD><B> 9. </B>the kernel of a seed. </DL>
<A NAME="nuclide">
<B>nuclide, </B>noun.<DL COMPACT><DD> a particular type of atom having a characteristic nucleus and a measurable life span. </DL>
<A NAME="nucule">
<B>nucule, </B>noun.<DL COMPACT><DD> (Botany.) a nutlet. </DL>
<A NAME="nude">
<B>nude, </B>adjective, noun.<DL COMPACT><DD><I>adj. </I> <B>1. </B>naked; bare; unclothed. <BR> <I>Ex. the nude trees of winter. (Figurative.) nude facts.</I> (SYN) undraped, stripped. <DD><B> 2. </B>(Law.) not supported or confirmed; made without a consideration; not actionable, as an agreement. <DD><I>noun </I> a naked human figure in painting, sculpture, or photography. <BR> <I>Ex. oldfashioned Rubenslike nudes (New Yorker).</I> <BR><I>expr. <B>the nude,</B> <DD><B> a. </B>the naked human figure. </I> <I>Ex. Modern chalk drawings, studies from the nude (Robert Browning).</I> <DD><B> b. </B>a naked condition. <BR> <I>Ex. to swim in the nude. Stands sublimely in the nude, as chaste As Medicean Venus (Elizabeth Barrett Browning).</I> adv. <B>nudely.</B> noun <B>nudeness.</B> </DL>
<A NAME="nudge">
<B>nudge</B> (1), verb, <B>nudged,</B> <B>nudging,</B> noun.<DL COMPACT><DD><I>v.t. </I> <B>1. </B>to push slightly; jog with the elbow to attract attention. <BR> <I>Ex. His next neighbors nudged him (Dickens).</I> <DD><B> 2. </B>(Figurative.) to prod; stimulate. <BR> <I>Ex. to nudge one's memory.</I> <DD><I>v.i. </I> to give a nudge or slight push. <DD><I>noun </I> a slight push or jog, as with the elbow. noun <B>nudger.</B> </DL>
<A NAME="nudge">
<B>nudge</B> (2) or <B>nudzh, </B>noun.<DL COMPACT><DD> (U.S. Slang.) <B>=nudnik.</B> <BR> <I>Ex. "He's not a writer, he's a nudge. On the phone twice a day asking how's it going!" (William Cole).</I> </DL>
<A NAME="nudibranch">
<B>nudibranch, </B>noun, adjective.<DL COMPACT><DD><I>noun </I> any one of a group of marine gastropod mollusks that usually have external adaptive gills and no shell when adult. <DD><I>adj. </I> of or belonging to this group. </DL>
<B>nudie, </B>noun.<DL COMPACT><DD> (Slang.) a motion picture, play, or magazine or other publication showing nude figures. </DL>
<A NAME="nudism">
<B>nudism, </B>noun.<DL COMPACT><DD> the practice of going naked, especially for health. <BR> <I>Ex. Nudism interwoven with socialism ... always shows a doctrinaire side. Going naked approaches being revolutionary; going barefoot is mere populism (New York Times).</I> </DL>
<A NAME="nudist">
<B>nudist, </B>noun, adjective.<DL COMPACT><DD><I>noun </I> a person naked, especially for health. <BR> <I>Ex. The nudists of France are pursued by the police, by the clergy, by the wit of Parisian cartoonists (John O'London's Weekly).</I> <DD><I>adj. </I> of nudism or nudists. <BR> <I>Ex. a nudist colony.</I> </DL>
<A NAME="nudity">
<B>nudity, </B>noun, pl. <B>-ties.</B><DL COMPACT><DD><B> 1. </B>a naked condition; nakedness. <DD><B> 2. </B>something naked; a nude figure, especially as represented in painting or sculpture. </DL>
<A NAME="nudnik">
<B>nudnik</B> or <B>nudnick, </B>noun.<DL COMPACT><DD> (Slang.) a tiresome, annoying person; bore; pest; crank. <BR> <I>Ex. I have another nudnick here who wants a round table like King Arthur's (S. J. Perelman).</I> </DL>
<B>nugatory, </B>adjective.<DL COMPACT><DD><B> 1. </B>of no value or importance; trifling; worthless. <BR> <I>Ex. ... sentimental interpretation of small part-songs of nugatory musical merit (London Times).</I> <DD><B> 2. </B>ineffective; useless. (SYN) futile. <DD><B> 3. </B>of no force; invalid. </DL>
<A NAME="nuggar">
<B>nuggar, </B>noun.<DL COMPACT><DD> a large, broad boat used on the Nile River for carrying cargo or troops. </DL>
<A NAME="nugget">
<B>nugget, </B>noun.<DL COMPACT><DD><B> 1. </B>a lump. <BR> <I>Ex. Stone Age man probably knew metals only as occasional nuggets of the precious metals (J. Growther).</I> <DD><B> 2. </B>a lump of native gold. <DD><B> 3. </B>anything valuable. <BR> <I>Ex. a nugget of wisdom.</I> <DD><B> 4. </B>(Australian.) a short, thick-set person or beast. </DL>
<A NAME="nuggety">
<B>nuggety, </B>adjective.<DL COMPACT><DD><B> 1. </B>having the form of a nugget; occurring in nuggets or lumps. <DD><B> 2. </B>(Australian.) short and sturdy. </DL>
<A NAME="nuisance">
<B>nuisance, </B>noun.<DL COMPACT><DD><B> 1. </B>a thing or person that annoys, troubles, offends, or is disagreeable; annoyance. <BR> <I>Ex. Flies are a nuisance. The quartering of soldiers upon the colonists was a great nuisance (H. G. Wells).</I> (SYN) plague, trouble, inconvenience. <DD><B> 2. </B>(Law.) anything annoying, harmful, or offensive to a community, or a member of it, especially to a property owner, and always as defined by law. </DL>
<A NAME="nuisancetax">
<B>nuisance tax,</B><DL COMPACT><DD> a tax that is annoying because it is collected in small amounts from consumers. </DL>
