Reduktion

Reduktion is a German noun meaning the act or process of reducing—making something smaller, fewer, or simpler. The term is used in many fields and often translates to reduction in English. Etymology traces to Latin reducere, "to lead back."

In chemistry, Reduktion denotes the gain of electrons by a species, accompanied by a decrease in oxidation state. It is the opposite of oxidation and occurs in redox reactions. Reducing agents such as hydrogen, carbon monoxide, certain metals, or electrical current drive reductions.

In mathematics and computer science, Reduktion is a formal transformation that converts one problem into another while preserving solvability. Reduktionen underpin complexity theory and computability; polynomial-time Reduktionen are used to classify problems (for example, NP-hardness).

In linguistics, Reduktion refers to phonetic or morphological reduction—processes that shorten or weaken sounds in unstressed syllables or omit elements. Vowel reduction is common in many languages and can alter pronunciation without changing meaning.

In music, Reduktion denotes an arrangement of a larger work for a smaller ensemble, such as a piano reduction of an orchestral score. In data analysis and statistics, dimensional reduction (or data reduction) lowers the number of variables while preserving as much information as possible.