# Centre (mathematics)

From Citizendium

(Redirected from Center (mathematics))

*This disambiguation page lists articles associated with the same or a similar title.*

In mathematics, **centre** may refer to:

- In an algebraic structure, elements that commute with every element of the structure
- The centre of a group, elements that commute with every group element
- The centre of a ring, elements that commute with every ring element

- The centre of a circle
- The centre of mass, centroid or barycentre of a geometrical figure
- In triangle geometry
- The centroid, intersection of the medians
- The circumcentre, intersection of the perpendicular bisectors of the sides, centre of the circle through the vertices
- The nine-point centre
- The orthocentre, intersection of the altitudes
- The incentre, centre of a circle tangent to the sides
- The excentres, centres of the three circles internally tangent to one side and externally to the other two