Definition of polar in English:

polar

adjective

  • 1Relating to the North or South Pole:

    ‘the polar regions’
    • ‘Increasing temperatures are gradually melting the polar ice caps at the north and south pole exposing us all to the devastating consequences of widespread flooding, over huge continents and not just in one local area.’
    • ‘Most North American cities will flood and sink when the polar ice caps melt and raise ocean levels.’
    • ‘There were no polar ice caps or continental glaciation.’
    • ‘The most dramatic effect would be an increase in sea levels due to melting of the polar ice caps causing many low-lying costal areas to flood.’
    • ‘The early Permian saw the continuation of the Carboniferous biomes, with polar tundra regions and warm wet tropical swamp forests.’
    • ‘It warns of adverse consequences such as the melting of glaciers and polar icecaps, leading to rising sea levels.’
    • ‘In mid December, the dog teams turned back, leaving the rest to face the ascent of the Beardmore Glacier and the polar plateau.’
    • ‘Glaciers, permafrost and polar ice caps are melting, and droughts, floods and more extreme storms are occurring more frequently in many parts of the world.’
    • ‘The polar ice caps have expanded, the sea-level has fallen, and a new plant has made its appearance: grass.’
    • ‘Remote echographic diagnostics also have a role to play in remote and emergency situations such as in many parts of the third world, the polar regions and at sea.’
    • ‘The eternal droughts and continental erosion and melting polar ice caps, that's what you call your collateral damage.’
    • ‘In the northern hemisphere the polar region is an ocean basin which is almost completely enclosed by surrounding major land masses.’
    • ‘Boston thinks the bots could also tackle challenging surface terrain on the red planet, including polar ice caps riddled with fissures.’
    • ‘There's evidence that the north polar ice cap melted 40 percent in just this century.’
    • ‘And also things like what's happening to the glaciers and the different mountain regions or the polar ice caps or ocean temperatures.’
    • ‘Northern Pakistan also boasts some of the longest glaciers outside the polar region.’
    • ‘Pipits and wagtails can be found in a variety of habitats from temperate to tropical and polar regions.’
    • ‘Their preferred habitat is the annual sea ice over the continental shelf and inter-island archipelagos that encircle the polar basin.’
    • ‘On land, giant reservoirs holding saline water could be built to offset the rise in sea levels caused by the melting of the polar ice-caps.’
    • ‘Based on growing evidence that climate shifts in the past have taken place with breathtaking speed, based on the freshening of sea water due to accelerated melting of glaciers and the polar ice caps.’
    arctic, antarctic
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    1. 1.1 (of an animal or plant) living in the north or south polar region:
      ‘most polar birds breed seasonally’
      • ‘Molecular dynamics analysis of a second phosphate site in the hemoglobins of the seabird, south polar skua.’
      • ‘But populations of frogs, butterflies, ocean corals, and polar birds have already gone extinct because of climate change, Parmesan said.’
      • ‘This theory suggested that polar marine invertebrates lack sufficient fish predation to drive natural selection for chemical means of protection.’
      • ‘Furthermore, it cannot migrate or hibernate during winter, as is thought possible for some polar dinosaurs and turtles.’
      • ‘They were found alongside the remains of mammoth, reindeer and polar fox, and they appear to have been eaten by their human masters.’
      • ‘The most striking of adaptations in polar sea animals is to the cold.’
      • ‘Since the initial discovery, the study of polar dinosaurs has slowly gained momentum.’
      • ‘But polar species are far fewer in number and may not face the same extinction risk as those that live in more confined hot spots with greater biodiversity.’
      • ‘One of the puzzles polar dinosaur specialists face is establishing how cold it was, at what time period, where.’
      • ‘The best characterized of these AFPs come from polar fish and from several different species of insects.’
      • ‘It's likely that there are wide metabolic variations among dinosaurs, and polar dinosaurs can begin to shed some light on the issue.’
      • ‘The discovery of the polar dinosaurs clearly suggests that they survived the volcanic winter that apparently killed other dinosaur species.’
      • ‘The results could be catastrophic for polar people and animals, while low-lying lands as far away as Florida could be inundated by rising sea levels.’
      • ‘The new discovery of polar dinosaurs is a problem for the meteorite theory, but can be explained within the Flood paradigm.’
      • ‘A footprint in polar moss, of which there are some 350 Antarctic varieties, lasts ten years.’
      • ‘One species bucked the general trend: the south polar skua, which hunts mainly penguin chicks and eggs.’
    2. 1.2Astronomy Relating to the poles of a celestial body:
      ‘the polar radius of Jupiter is 66,550 km’
      • ‘Also there are areas at higher elevation on the rim of polar craters that see the Sun more than half of the time.’
      • ‘This means that its equatorial radius would be 40 kilometers greater than the polar radius.’
      • ‘Then, in early January, it made a series of planned manoeuvres to change its equatorial orbit to a polar one, to prepare for its scientific mission and to make contact with Beagle 2.’
      • ‘Scientists will also dig into the puzzling asymmetry in the Sun's magnetism that was discovered by Ulysses during the first polar passes.’
      • ‘However, there may be water locked in permafrost in some deep polar craters.’
    3. 1.3Astronomy Relating to a celestial pole.
    4. 1.4Geometry Relating to the poles of a sphere.
      See pole
      • ‘The Earth is an oblate spheroid, with polar diameter some 45 km less than the equatorial diameter.’
    5. 1.5Biology Relating to the poles of a cell, organ, or part.
      • ‘Angiosperm seeds are comprised of an embryo and endosperm resulting from double fertilization of the egg cell and two polar nuclei, respectively.’
      • ‘To circumvent the problems of interpreting results in an organ with a diverse population of cells, it was decided to study the induction of polar growth in individual cells.’
      • ‘Moreover, the endosperm is formed due to the fusing of two polar nuclei cells with a sperm nucleus.’
      • ‘Class 1 mutations (b and c) elongate cells and cause predominantly polar bud site selection.’
      • ‘The most utilized fluorescent markers of dead cells are polar DNA-binding dyes, unable to penetrate intact plasma membranes.’
  • 2Physics Chemistry
    Having electrical or magnetic polarity.

    • ‘It is polar, that is the oxygen atom has a negative electrical charge while the two hydrogen atoms are positive.’
    • ‘Polar interactions require a nonsymmetric arrangement of bonds with atoms of different electronegativity - polar bonds.’
    • ‘Charged and polar residues played an important role due to favorable electrostatic interactions.’
    • ‘Another active area of biophysical research concerns the study of the interactions involving charged, polar and polarizable groups of atoms in proteins.’
    • ‘For example, HCl comprised of the atom Hydrogen and Chlorine is polar.’
    1. 2.1 (of a liquid, especially a solvent) consisting of molecules with a dipole moment.
      • ‘Recent work in our laboratory has explored the clustering behaviour of organic polar solvents such as methanol, 6 ethanol and butanol.’
      • ‘In addition, the growth of coatings containing higher levels of solids such as epoxy resins, polyesters and urethanes has increased the demand for polar solvents such as ethyl acetate.’
      • ‘Strangely, this chimes with homoeopathic beliefs about the way that remedies become more active by increased dilution in polar solvents like water.’
      • ‘All electrolytes dissociate to some extent in polar solvents.’
      • ‘With sodium chloride and water, the saturated condition is rapidly reached because the attraction between the sodium chloride ions and the polar water molecules is so strong.’
    2. 2.2 (of a solid) ionic.
      • ‘Electronegativity can be used to predict whether a bond will be a nonpolar covalent bond, a polar covalent bond, or an ionic bond.’
      • ‘In addition, the dipolar water molecules are supposed to be strongly bound to ionic and polar parts along the protein surface.’
      • ‘The C-Cl bond is polar covalent, Na-Cl is ionic, and the C-C bond is pure covalent with each atom sharing the bonding electrons equally.’
      • ‘The compound lithium hydride, LiH, is a polar covalent solid that reacts with water to liberate hydrogen gas and form basic solutions of the metal hydroxide.’
      • ‘Uncharged polar and even ionic dyes with substantial molar weights have often been used to trace apoplastic water movement.’
  • 3Directly opposite in character or tendency:

    ‘depression and its polar opposite, mania’
    • ‘Where the film excels is in comparing and contrasting the two ostensibly polar opposite schemes.’
    • ‘Which brings up the point of polar opposites co-existing, and hence the harmonious balance which the world strives to keep is always unbalanced.’
    • ‘Sitting in his sunny front room silhouetted in the bay window, white t-shirt, tartan shorts and sports socks, he is sartorially the polar opposite of the traditional bow-tie and tails combo.’
    • ‘At first blush, the two appear to be polar opposites.’
    • ‘Elizabeth relates to Alice and treats Leisha with distance and disdain; Roger's reactions are the polar opposite.’
    • ‘But the true polar opposite of Belfast in terms of atmosphere and natural splendor has got to be the town of Killarney in County Kerry, southwestern Ireland.’
    • ‘Rob and Ann are such polar opposites that it seems unlikely they'd move beyond physical attraction in the few days they spend together before getting married.’
    • ‘So, data from wall power, the scary concept of flying cars in the hands of slow-drivers who can barely see over the wheel, and patent cooperation between two seeming polar opposites.’
    • ‘But then again the two characters could never be described as polar opposites.’
    • ‘It's like the polar opposite of San Francisco startup life (not that I'm an expert in that already, but I have a good idea of what it's like).’
    • ‘Most are somewhere between these polar opposites.’
    • ‘The parties are practically polar opposites when it comes to dealing with youth crime and they have more than their share of differences over the kinds of reforms needed to turn around failing schools and hospitals.’
    • ‘Filmmakers' hours are the exact polar opposite of musician's hours: filmmaking begins early in the morning and ends when the sun goes down.’
    • ‘But something close to the polar opposite has now occurred.’
    • ‘Every time it comes to the forefront, you're caught off guard, as it's polar opposite of the main comedic tendencies of the film.’
    • ‘The offer is open to all parties, but with Labour expected to once again emerge on top, the Tory plan enables the remarkable prospect of the two polar opposites of British politics working together.’
    • ‘In the technological revolution that digital video has brought to filmmaking, these two works represent polar opposites of the brave new world.’
    • ‘Now, so soon after that, we get the polar opposite.’
    • ‘They are kidnapped, and spend a terrifying four years together in grim captivity - polar opposites unexpectedly finding a passionate friendship and comradeship in adversity.’
    • ‘The Andante moderato is dead serious, as though ‘String Quartet’ and fun were two polar opposites.’
    opposite, opposed, opposing, oppositional, diametrically opposed, extreme, contrary, contradictory, antithetical, antagonistic, conflicting, counterbalancing
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noun

  • 1Geometry
    The straight line joining the two points at which tangents from a fixed point touch a conic section.

    • ‘This exactly means that the directrix is the polar of the focus, while the focus is the pole of the directrix with respect to the parabola.’
    • ‘Inserting a waveplate at a 45° angle to the crossed polars in an optical microscope allows the determination of the orientation of the amyloid fibrils within the spherulites.’
    • ‘Bobillier is best known for his work on polars of curves and of algebraic surfaces.’
    • ‘Sturm's theoretical work in mathematical physics involved the study of caustic curves, and poles and polars of conic sections.’
    • ‘The apparatus of algebraic geometry is built upon polars, and these upon distances.’
  • 2Astronomy
    A variable binary star which emits strongly polarized light, one component being a strongly magnetic white dwarf.

Origin

Mid 16th century: from medieval Latin polaris heavenly, from Latin polus end of an axis (see pole).

Pronunciation

polar

/ˈpəʊlə/