reversal

Reversal is the act of turning something back or in the opposite direction, or the process of changing a course, sign, order, or condition. It is used across many fields to describe a switch from one state to another.

In physics and cosmology, time reversal refers to reversing the direction of time in the equations of motion. Some laws are symmetric under time reversal, but thermodynamic irreversibility, energy dissipation, and the arrow of time typically break symmetry.

In finance, a reversal denotes a change in the prevailing price trend. Traders distinguish trend reversals from continuations. Reversal signals may arise from chart patterns, volume shifts, or momentum indicators.

In language and literature, reversal or inversion is a stylistic device that changes the natural word order for emphasis or effect, such as inverted sentences or chiasmus.

In medicine and pharmacology, reversal refers to agents or interventions that counteract a drug’s effects or restore baseline function, such as reversal agents for anesthesia or anticoagulation.

In biology and genetics, reversion describes a mutation that restores the original phenotype or function; reversions can be spontaneous or induced and are studied in genetics research.