in·ver·sion / inˈvərzhən/ • n. 1. the action of inverting something or the state of being inverted: the inversion of the normal domestic arrangement. ∎  reversal of the normal order of words, typically for rhetorical effect but also found in the regular formation of questions in English. ∎  Mus. the process of inverting an interval, chord, or phrase. ∎  Mus. an inverted interval, chord, or phrase. ∎  Physics (also population inversion) a transposition in the relative numbers of atoms, molecules, etc., occupying particular energy levels. ∎  Chem. a reaction causing a change from one optically active configuration to the opposite configuration, esp. the hydrolysis of dextrose to give a levorotatory solution of fructose and glucose. ∎  Physics the conversion of direct current into alternating current.2. (also temperature inversion 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. Math. 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 that gives a given expression under a given transformation. ∎  Geom. a transformation in which each point of a given figure is replaced by another point on the same straight line from a fixed point, esp. in such a way that the product of the distances of the two points from the center of inversion is constant.4. (also sexual inversion) dated Psychol. the adoption of behavior typical of the opposite sex; homosexuality.DERIVATIVES: in·ver·sive / -ˈvərsiv/ adj.

inversion A reversal of a particular trend.

1. A rock sequence in which the younger sediments are at the bottom. Inversion can be caused by overfolding or thrusting. It is a major feature of an accretionary wedge in which progressively younger oceanic and trench sediment is underthrust, so that while each thrust slice is not inverted, each new thrust affects younger sediment, so producing the inversion. In a positive inversion, normal faults on passive margins become thrusts on collision. In a negative inversion thrusts become normal faults at the end of an orogeny. The inversion of sediments takes place during strike-slip faulting.

2. During an orogeny, the uplift that follows subsidence as a reversal of vertical direction.

3. Seismic velocity usually increases with depth, but occasionally a zone of anomalously low velocity occurs between layers of higher velocities giving rise to a velocity inversion.

4. See polarity reversal.

5. See TEMPERATURE INVERSION.

INVERSION, also anastrophe.
1. Turning something round, as for example in English, when forming certain kinds of QUESTIONS from statements, such as Are you coming? from You are coming, by inverting the order of you are.

2. In RHETORIC, speech in which the normal word order of statements is turned round, usually for emphasis or to mark priority and eminence: ‘To the Most High and Mightie Prince, Iames by the grace of God King of Great Britaine, France and Ireland, Defender of the Faith, &c. the Translators of the Bible wish grace Mercie, and Peace through Iesus Christ our Lord’ (dedication, the Authorized Version of the Bible, 1611). Journalistic uses of inversion that are often regarded as vices include inverting verb and subject in reporting clauses that come before quoted statements: for example, Says Darren Beagle, chief programmer at Megabux Inc., ‘This is the breakthrough we've all been waiting for.’ See CHIASMUS, QUESTION, WORD ORDER.

inversion (in genetics)
1. A chromosome mutation caused by reversal of part of a chromosome, so that the genes within that part are in inverse order. Inversion mutations usually occur during crossing over in meiosis.

2. A point mutation caused by the reversal of two or more bases in the DNA sequence within a gene.

inversion A change in the arrangement of genetic material, involving the excision of a chromosomal segment that is then turned through 180° and reinserted at the same position in the chromosome. The result is a reversal in the order of genes in that segment of chromosome.