Noun, pl. inversions
1. The action of inverting. (wiktionary.org)
2. Being upside down, in an inverted state. (wiktionary.org)
3. Being in a reverse sequence, in an inverted state. (wiktionary.org)
4. (Kinesiology) Movement of the sole towards the median plane.
6. (Weather) An increase of air temperature with increase in altitude (the ground being colder than the surrounding air). When an inversion exists, there are no convection currents and wind speeds are below 5 knots. The atmosphere is stable and normally is considered the most favorable state for ground release of chemical agents. (wiktionary.org)
7. (Chemistry) Conversion of a substance in which the direction of optical rotation is reversed, from the dextrorotatory to the levorotatory or from the levorotatory to the dextrorotatory form. (medical-dictionary.thefreedictionary.com)
Word origin: From Latin inversionem (nominative inversio) “an inversion,” noun of action from past participle stem of invertere