unipolaradj.n.
/juːnɪˈpəʊlə/, U.S. /junəˈpoʊlər/ 1. Physics.
a. Produced by or proceeding from a single magnetic pole; exhibiting or employing a single polarity (magnetic or electrical).
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the world > matter > physics > electromagnetic radiation > electricity > electric polarization > [adjective] > relating to poles > exhibiting single polarity
unipolar1806
monopolar1892
the world > matter > physics > electromagnetic radiation > electricity > electric polarization > [adjective] > relating to poles > exhibiting single polarity > during induction
unipolar1806
1806 Philos. Mag. 24 185 M. Herman..has divided them into insulated bodies, into perfect and imperfect conductors, and into uni-polar and bi-polar bodies, according as their conductible property manifests itself at both, or only at one of the extremities of the pile.
1873 J. C. Maxwell Treat. Electr. & Magnetism II. 7 The property produced by magnetism in transparent bodies of twisting the plane of polarization of the incident light, is, like magnetism itself, a unipolar property.
1878 Brit. Med. Jrnl. 12 Oct. 552/1 Platinum-plates, charged with prolonged electricity, could bring about this relapsing anæsthesia; also a single electrode of an isolated pile, that is to say, a rigorously unipolar application.
1893 D. Turner Man. Pract. Med. Electr. v. ii. 238 The electrode may be applied in a ‘unipolar’ or in a ‘bipolar’ manner.
1987 Nature 17 Dec. 635/1 The charge clouds in the regions between flame and each electrode are unipolar.
2004 Progress Colloid & Polymer Sci. 128 20/1 The interaction of a strong electric field with the space charge near the surface of unipolar (ionically or electronically) conducting particles.
b. Of apparatus: having, or operating by means of, a single magnetic pole; (of a generator or motor) involving or employing unipolar induction (= homopolar adj. 2).
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the world > matter > physics > electromagnetic radiation > electricity > electrical engineering > operation of machinery > [adjective] > having many poles
unipolar1876
multipolar1884
the world > matter > physics > electromagnetic radiation > magnetism > magnetic devices or materials > [adjective] > polar > having one or two poles
dipolar1864
unipolar1876
1876 Nature 20 July 263/2 A unipolar magnetic needle.
1883 Daily News 10 Sept. 2/2 The remarkable machine of Messrs. Siemens and Halske, called the unipolar machine.
1920 Whittaker's Electr. Engineer's Pocket-bk. (ed. 4) 139 Unipolar machines have not been able to compete with heteropolar types.
1975 Nature 6 Feb. 416/2 The satellite Io acts as a unipolar inductor and a source of constant e.m.f. across the Io flux tube as it moves through the Jupiter magnetic field.
2012 J. Sanchez & M. P. Canton Embedded Syst. Circuits & Programming xv. 382 The circuit of a unipolar stepper motor is very simple.
2. Biology.
a. Of a nerve cell: having a single process (typically an axon); (in later use also) having only one dendrite.
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the world > life > the body > nervous system > substance of nervous system > [adjective] > nerve cell > types of
unipolar1853
interneural1888
adendritic1894
interneuronal1899
tigroid1901
connecter1916
satellited1928
microglial1929
oligodendroglial1929
presynaptic1935
postsynaptic1937
motoneuronal1955
fusimotor1958
monoaminergic1963
noradrenergic1963
aminergic1967
1853 Assoc. Med. Jrnl. 18 Nov. 1016/1 At the extremity of each branch, there is seated a ganglionic cell, fixed on it ‘like a pear by its stalk’, and hence ‘unipolar’.
1872 A. Flint Physiol. Man IV. i. 46 Unipolar cells exist in some of the lower orders of animals.
1880 H. C. Bastian Brain ii. 48 Unipolar nerve cells..are alleged to exist in the ganglia on the spinal nerves and elsewhere.
1947 A. D. Imms Outl. Entomol. (ed. 3) ii. 26 The motor neurones..are mostly unipolar and their axons form an efferent or motor nerve.
2005 A. B. Butler & W. Hodos Compar. Vertebr. Neuroanat. (ed. 2) xiv. 254/2 Unipolar brush cells have been found in many mammalian species, including macaque monkeys.
b. Of a rete mirabile: supplied by only one side (usually arterial) of the circulatory system.
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the world > life > the body > vascular system > blood vessel > [adjective] > others
recurrent1578
subserous1827
unipolar1862
1862 Nat. Hist. Rev. 2 102 The tibio-tarsal rete mirabile of this wingless bird is therefore unipolar.
1878 F. J. Bell & E. R. Lankester tr. C. Gegenbaur Elements Compar. Anat. 597 If the rete remains broken up, then it is known as a diffuse, unipolar, or monocentric rete mirabile.
1924 Philos. Trans. (Royal Soc.) B. 212 228 The whole forming a simple rete, differing from those of Müller's unipolar type only in the fact that the individual twigs do not anastomose to form a true plexus.
2009 B. Pelster in M. L. Glass & S. C. Wood Cardio-Respiratory Control Vertebr. 71 After leaving the rete mirabile in an unipolar rete the capillaries almost directly supply a special area of the swimbladder epithelium.
3. Electronics. Of a transistor or similar device: involving conduction by charge carriers of a single polarity.
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the world > matter > physics > solid state physics > semiconductivity > [adjective] > other attributes of semiconductors or devices
unipolar1952
planar1965
1952 W. Shockley in Proc. IRE 40 1313/1 In order to distinguish between the more conventional transistors and the analog types, we propose to use the words bipolar and unipolar.
1973 Sci. Amer. Aug. 48/2 Most integrated circuits produced in the 1960's were of the bipolar type, but production of the newer unipolar type is growing rapidly.
1981 J. C. Sprott Introd. Mod. Electronics viii. 169 The FET..is an example of a unipolar device.
2011 K. F. Renk Basics Laser Physics (2012) xx. 371 The unipolar semiconductor lasers, realized as quantum cascade lasers, belong to the three-level laser type.
4. Psychiatry. Of a mental illness: characterized by symptoms of only one category of affective disorder; spec. designating depression in which there is no element of mania; cf. bipolar disorder n. at bipolar adj. Additions. Also: affected by such an illness.
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the world > health and disease > mental health > mental illness > degree or type of mental illness > [adjective] > depressive > characterized by depressive episodes
unipolar1965
1965 Acta Psychiatrica Scandinavica Suppl. 87 We..have assumed that ‘middle age depressions’ according to Stenbäck and ‘unipolar depressions’ according to Leonhard are merely different terms, which..cover the same nosographic entity.
1975 Arch. Gen. Psychiatry 32 866/2 There may be more than one type of unipolar or bipolar disorder.
1997 D. Singh Khalsa & C. Stauth Brain Longevity xix. 397 Deprenyl and phenylalanine, used together, achieved a ‘full recovery’ in 65 percent of patients who were suffering from clinical unipolar depression.
2009 P. R. Robbins Understanding Depression (ed. 2) i. 25 The unipolar patients tended to be insecure and introverted.
5. Politics. Characterized by the dominance of a single nation.
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1990 C. Krauthammer in Foreign Affairs 70 23 It has been assumed that the old bipolar world would beget a multipolar world with power dispersed to new centers... The immediate post-Cold War world is not multipolar. It is unipolar.
1990 C. Krauthammer in Foreign Affairs 70 24 Now is the unipolar moment.
1992 N.Y. Rev. Bks. 9 Apr. 40/3 Those who talk of a unipolar world confuse America's unmatched military might with a preponderance of real power.
1998 Independent 23 Apr. i. 14/7 In the wake of Soviet collapse, the ‘unipolar’ globe needed an overarching theory.
2003 Vanity Fair July 117/2 To be a neocon today is to believe that the optimal world is one in which the United States asserts its might and promulgates its ideas, embracing its ‘unipolar’ status, whether or not other nations agree.
2014 N.Y. Rev. Bks. 10 July 53/1 The Francis Fukuyama moment—when in 1989 Westerners were told that liberal democracy was the final form toward which all political striving was directed—now looks like a quaint artifact of a vanished unipolar moment.
Compounds
unipolar induction n. [after German †unipolare Induction (W. Weber in Resultate aus den Beobachtungen der magnetischen Vereins im Jahre 1839 (1840) 64); now unipolare Induktion] electrical induction in which a continuous direct current is produced by the relative rotation of a conductor and the magnetic field in which it is situated; cf. homopolar adj. 2.
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the world > matter > physics > electromagnetic radiation > electricity > electrically induced magnetism > electromagnetic induction > [noun]
excitation1656
induction1801
magnetic induction1851
unipolar induction1856
influence1870
magneto-induction1889
unipole1892
1856 C. V. Walker tr. A. de la Rive Treat. Electr. II. 13 With induction, also, is connected Weber's phenomenon, known by the name of unipolar induction.
1888 Encycl. Brit. XXIII. 330/1 The so-called ‘unipolar’ induction supposed to be due to the rotation of the earth.
1982 Astrophysical Jrnl. 262 87 A potential drop ∼1019 volts is generated by the unipolar induction of a rotating accretion disk surrounding the black hole.
2008 B. Punsly Black Hole Gravitohydromagn. (ed. 2) vii. 215 The pulsar is still viable because the unipolar induction of the neutron star can drive MHD [= magnetohydrodynamic] currents.
This entry has been updated (OED Third Edition, September 2015; most recently modified version published online June 2022).
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adj.n.1806