midspheres

Noun

midsphere (plural midspheres)

1. A middle sphere or region.
   • For rescue or personnel-transfer purposes, the midsphere could also, like DSRV, be equipped with a transfer bell.1968, Space Aeronautics, volume 49, page 61
2. (solid geometry) The sphere which, if it exists, is tangent to every edge of a given polyhedron and with respect to which the polyhedron's vertices are the inversion poles of the planes of the faces of its dual polyhedron (and vice versa).
   • The edges are omitted as irrelevant to the present argument, but the midspheres are still included because Kepler rather casually substitutes the midsphere for the insphere of the octahedron, since it happens to give a value closer to the observed distance.1999, Richard Padovan, Proportion: Science, Philosophy, Architecture, page 260

   Synonyms:

   intersphere, inversion sphere, reciprocating sphere

3. The sphere, between two given spheres, by which each of the latter may be inverted into the other.
   • For any two circles (spheres) there always exists at least one midcircle (midsphere) which inverts the two given circles (spheres) into each other. in the older literature this is also known as the circle (sphere) of antisimilitude. […] The center of a midcircle (midsphere) is the center of...1994, Tim Gallagher, Bruce Piper, Chapter 7: Convexity Preserving Surface Interpolation, Nickolas S. Sapidis, Designing Fair Curves and Surfaces, page 179

   Synonyms:

   sphere of antisimilitude

4. (Vedic, uncountable) A supposed realm between earth and heaven.
   • This celestial river (Nadī) transforms into [the] terrestrial one (sindhu) after falling from heaven (midsphere) in the form of rain-drops.2003, Ravi Prakash Arya, New discoveries about Vedic Sarasvatī, page 22