torus
/ˈtɔːrəs
/noun (plural tori /ˈtɔːrʌɪ/ or toruses)
1 Geometry A surface or solid formed by rotating a closed curve, especially a circle, about a line which lies in the same plane but does not intersect it (e.g. like a ring doughnut).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....
- A small patch of a sphere or torus surface looks almost like a piece of a flat plane and has area rather than volume.
- ‘In other words, each solution could be drawn on the surface of a torus,’ he notes.
1.1A ring-shaped object, especially a large ring-shaped chamber used in physical research.Like tokamaks, their currently more advanced cousins, stellarators use magnetic fields to confine plasma in a torus for fusion reactions....
- 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.
- 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.
2 Architecture A large convex moulding, typically semicircular in cross section, especially as the lowest part of the base of a column.One stand has a torus molding with red-painted triglyph and metopal sections, while a lower register has alternating black and white sections....
- A long cylindrical bar of orange-painted steel evokes a tori (temple gate) and serves as a balustrade.
- 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.
3 Anatomy 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 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.
4 Botany The receptacle of a flower.
Origin
Mid 16th century (in sense 2): from Latin, literally 'swelling, bolster, round moulding'. The other senses date from the 19th century.