Definition of torus in English:



  • 1Geometry
    A surface or solid formed by rotating a closed curve, especially a circle, around a line that lies in the same plane but does not intersect it (e.g., like a ring-shaped doughnut)

    • ‘The surface area of the inside portion of a torus can be obtained by integrating Eq. 4, which yields’
    • ‘The resulting surface is a two-manifold called a torus.’
    • ‘Because the two periods are not related by an integer but are incommensurate, the system does not flow toward a closed path but instead orbits without converging on the surface of the torus.’
    • ‘To be rigorous, the hole is not actually in the torus: the torus is the surface and the hole is in the space around the surface.’
    • ‘We can also represent the flat hexagonal torus as a tiling of flat space, as in fig.9.’
    • ‘The surface of a sphere is a good example, as is a torus (the mathematical name for the shape of the surface of a quoit, or a ring-shaped doughnut).’
    • ‘I found there that the solution of Archytus involves three surfaces - torus, cylinder, and cone.’
    • ‘You can see a movie of a flat surface becoming a torus at this page about Paper Strip Activities.’
    • ‘Intuitively, this is a consequence of the fact that two lineages can be functionally separated by a greater distance in a rectangle than in a torus.’
    • ‘‘It appears the torus is rotating like a wheel,’ she continued.’
    • ‘‘And it stands to reason that they would have other toruses dotting the quadrant,’ Maria speculated.’
    • ‘Into how many pieces can one cut a torus using two planes?’
    • ‘‘In other words, each solution could be drawn on the surface of a torus,’ he notes.’
    • ‘To avoid edge effects, the lattice is represented on a circle for a one-dimensional model or a torus for a two-dimensional model.’
    • ‘All the quasi-fuchsian subgroups correspond to pairs of once-punctured tori, but as one tends to the boundary a certain curve on one of the tori may get squeezed to a point.’
    • ‘A small patch of a sphere or torus surface looks almost like a piece of a flat plane and has area rather than volume.’
    • ‘The Clifford torus is generated by a family of circles.’
    • ‘A bagel can serve as a physical model for a mathematical surface called a torus.’
    • ‘There are three classical attractors, a point which characterises a steady state system, a closed loop which characterises a periodic system, and a torus which combines several cycles.’
    • ‘In the formula of the curve given above the torus is formed from a circle of radius a whose centre is rotated along a circle of radius r.’
    1. 1.1A thing of this shape, especially a large ring-shaped chamber used in physical research.
      • ‘The innermost sections have the shape of a torus, but at Z 15 the edge of the channel opened to the bulk.’
      • ‘By carefully accounting for the particles injected into the machine and for those exhausted in the pumping system we found a deficit, indicating that a large fraction of deuterium gets trapped in the walls and components inside the torus.’
      • ‘A set of six hoop coils around the outside of the machine produces the magnetic field that shapes and positions the plasma centrally in the torus.’
      • ‘Hence the results presented for the torus will have general relevance for vestibular channels.’
      • ‘In some cases, astronomers can look along the axis of the dust torus from above or from below and have a clear view of the black hole.’
      • ‘The downfield resonance is attributed to molecules (mostly DCPC) on the highly curved region of the bicelle torus.’
      • ‘Cassini will cross the torus of dust in Enceladus' orbit and must turn to a protective attitude.’
      • ‘The ships were built around a torus shaped Spacial-Warp core.’
      • ‘It is possible that in this scan area the vesicles were not well dispersed; however, we cannot discount the possibility of irregular shapes being formed in addition to the torus and horseshoe shapes.’
      • ‘The Constitution fired one shot from a single turret, blasting a hole into one side of the torus that formed the bulk of the station.’
      • ‘The defense platform was a torus with three large solar panel arrays extending out from it with 120 degrees between them.’
      • ‘Surrounding the pulsar is a bright doughnut-shaped, or toroidal, structure, with jet-like features extending in a perpendicular direction away from the torus.’
      • ‘This remarkable device consists of a torus of alternating magnetic materials that are chosen so that the torus has a huge net spin - 10 22 aligned electron spins - yet produces no magnetic field.’
      • ‘‘He's good,’ Maria said as she angled the ship to orbit the torus.’
      • ‘The floor curved more gradually along the torus, so that the rows of apple and plum trees seemed to rise up on the side of a rolling hill, above the top of the nearby hay, until they disappeared in the horizon defined by the artificial sunlight.’
      • ‘Mark wondered why the rotating torus wasn't crushed from the tremendous gravitational forces at the mouth of the wormhole.’
      • ‘Nat Fisch of Princeton University and his colleagues propose driving the current by adding energy in only a small region, rather than everywhere around the torus.’
      • ‘Like tokamaks, their currently more advanced cousins, stellarators use magnetic fields to confine plasma in a torus for fusion reactions.’
      • ‘The shuttle left the station at the same time that the invisible ship, the Sentinel, left their orbit for the torus.’
      • ‘When a neutron star binary coalesces, the rapidly spinning merged system is expected to form a spinning black hole, orbited momentarily by a torus of neutron-density matter.’
  • 2Architecture
    A large convex molding, typically semicircular in cross section, especially as the lowest part of the base of a column.

    • ‘The gadrooned flattened torus moulding, shown on the shelf or footrest of the stand in the engraving also appears on the stretchers of the Blenheim stands.’
    • ‘A long cylindrical bar of orange-painted steel evokes a tori (temple gate) and serves as a balustrade.’
    • ‘One stand has a torus molding with red-painted triglyph and metopal sections, while a lower register has alternating black and white sections.’
  • 3Anatomy
    A ridge of bone or muscle.

    ‘the maxillary torus’
    • ‘The supraorbital torus is lost in most modern humans, and ridging above the orbits in general is very reduced.’
    • ‘A longitudinal ridge of the bony palate, torus palatinus, may be present in the region of the median palatine suture and extends laterally from it.’
    • ‘Other names are ‘occipital spur or torus occipitalis’, it is the insertion site of the ligamentum nuchae.’
    • ‘There is no continuous torus; the very robust glabella and superciliary arches are well defined’.’
    • ‘A torus, or ‘buckle,’ fracture of the distal radius is a common type of fracture in children.’
    • ‘In children, the most common injury is the torus fracture, which occurs with a fall onto an outstretched hand.’
    • ‘Also common is torus palatinus, a slow growing, asymptomatic, benign bony lump in the midline of the palate.’
  • 4Botany
    The receptacle of a flower.


Mid 16th century ( torus): from Latin, literally swelling, bolster, round molding The other senses date from the 19th century.