A chord of a circle or a sphere that passes through its centre.
- płaszczyzna średnicowa - diametral plane
a plane that passes through the centre of a sphere - średnica kątowa obiektu - angular diameter
an angle with a vetrex in a given point subtended by a given object - średnica stożkowej centralnej - diameter of a central conic
a line segment through the centre of the conic - średnice sprzężone - conjugate diameters
a pair of diameters of a central conic, each of them being a locus of midpoints of all chords parallel to the second diameter
- średnice równosprzężone - equiconjugate diameters
conjugate diameters of the same length - średnica figury - span of a figure
supremum (or least upper bound = lub) of leghts of line segments with endpoints within the figure