Definition of "inversion"

inversion

/ɪnˈvɚ.ʒən/

noun
countable and uncountable, plural inversions
1. The action of inverting.
2. The act of being in an inverted state; being upside down, inside out, or in a reverse sequence.
3. (music) The reversal of an interval; the move of one pitch in an interval up or down an octave.
4. (music) The position of a chord which has a note other than the root as its bass note.
5. (music) The flipping of a melody or contrapuntal line so that high notes become low and vice versa; the reversal of a pitch contour.
6. (genetics) A segment of DNA in the context of a chromosome that is reversed in orientation relative to a reference karyotype or genome.
7. (meteorology) A situation where air temperature increases with altitude (the ground being colder than the surrounding air).
8. A section of a roller coaster where passengers are temporarily turned upside down.
9. (grammar) Deviation from standard word order by putting the predicate before the subject. It takes place in questions with auxiliary verbs and in normal, affirmative clauses beginning with a negative particle, for the purpose of emphasis.
  Quotations
  Question formation involves the phenomenon commonly known as subject-auxiliary inversion, a change in word order in which the auxiliary moves in front of the subject. (a) Here we shall describe this phenomenon in terms of movement of the element under INFL into COMP position.(b) According to this analysis, what looks like an exchanging of positions between the subject and auxiliary (or INFL element, in GB terms) is actually the movement of the INFL element past the subject position into COMP. (c) INFL-to-COMP movement seems to be triggered by the presence of the [+WH] feature in COMP.
  2007/08, abergs, “INFL-to-COMP movement”, in English Language and Linguistics Online‎, retrieved 2014-05-22
10. (algebra) An operation on a group, analogous to negation.
11. (psychology, obsolete) Homosexuality, particularly in early psychoanalysis.
  Quotations
  We can seldom, therefore, congratulate ourselves on the success of any "cure" of inversion.
  1897, W. Havelock Ellis, Sexual Inversion, page 202
  My father, León Fuertes, was a fag three years; […] He put on all the trappings of inversion: the twittered mouthings, the hyper-feminine moues, the languid mincings.
  1975, R. M. Koster, The Dissertation, page 118