inversion

noun

• 1 [mass noun] the action of inverting something or the state of being inverted:the inversion of the normal domestic arrangement [count noun]:an inversion of traditional customer-supplier relationships
• reversal of the normal order of words, typically for rhetorical effect but also found in the regular formation of questions in English.
• Music the process of inverting an interval, chord, or phrase.
• [count noun] Music an inverted interval, chord, or phrase.
• Physics (also population inversion) a transposition in the relative numbers of atoms, molecules, etc. occupying particular energy levels.
• Chemistry a reaction causing a change from one optically active configuration to the opposite configuration, especially the hydrolysis of dextrose to give a laevorotatory solution of fructose and glucose.

• 2 (also temperature or thermal inversion) a reversal of the normal decrease of air temperature with altitude, or of water temperature with depth.
• (also inversion layer) a layer of the atmosphere in which temperature increases with height.

• 3 [mass noun] Mathematics the process of finding a quantity, function, etc. from a given one such that the product of the two under a particular operation is the identity.
• the interchanging of numerator and denominator of a fraction, or antecedent and consequent of a ratio.
• the process of finding the expression which gives a given expression under a given transformation.
• [count noun] Geometry a transformation in which each point of a given figure is replaced by another point on the same straight line from a fixed point, especially in such a way that the product of the distances of the two points from the centre of inversion is constant.

• 4 (also sexual inversion) Psychology, dated homosexuality.