Superposition

Superposition means that several things are combined by putting one on top of the other. More specifically, the term has several meanings:

 In mathematics, linear equations can be combined, and in certain cases, solutions can be found more easily.
 In physics, the superposition principle states that if there are two or more stimuli at a given point in time, the response will be the result of adding all the responses. This only applies to linear systems. Since many systems can be modeled as linear systems, the principle has many applications in physics and engineering.
 In biology, alternative splicing means that certain sequences of DNA can be used for more than one protein.
 In geology and archaeology, the Law of Superposition states that layers further down are usually older than those more at the top.