torus

plural tori · plural toruses

1. The standard representation of such a space in 3-dimensional Euclidean space: 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).
   1. geometryA topological space which is a product of two circles.

      A 4-variable Karnaugh map can be thought of, topologically, as being a torus.

      Synonyms: toroid

   2. in compoundsusuallygeometryThe product of the specified number of circles.

      Synonyms: toroid

   3. geometryA ring-shaped object, especially a large ring-shaped chamber used in physical research.

      Synonyms: toroid

2. architectureA large convex molding, typically semicircular in cross section, which commonly projects at the base of a column and above the plinth.
3. anatomyA rounded ridge of bone or muscle, especially one on the occipital bone.

   1 more example

   While there is a hereditary component to tori, this does not explain all cases. Tori tend to appear more frequently during middle age of life; the torus palatinus is more commonly observed in females, but this is not the case with the torus mandibularis. Certain ethnic groups are more prone to one torus or the other.

   2010 March, Andrés S. García-García, José-María Martínez-González, Rafael Gómez-Font, Ángeles Soto-Rivadeneira, Lucia Oviedo-Roldán, “Current status of the torus palatinus and torus mandibularis”, in Oral Surgery, volume 15, number 2, page 353

4. biologyThe end of the peduncle or flower stalk to which the floral parts (or in the Asteraceae, the florets of a flower head) are attached.

   Synonyms: receptacle, thalamus

5. biologyThe thickening of a membrane closing a wood-cell pit (as of gymnosperm tracheids) having the secondary cell wall arched over the pit cavity.