analoger

Analoger, plural of analogue (British spelling) or analog (American spelling), is a term used across science and technology to describe entities that resemble each other in form or function but are not identical. The exact meaning varies by field, yet the core idea is similarity without sameness or direct origin.

In chemistry and pharmacology, structural analogs are compounds with similar molecular skeletons. Small substitutions can change properties such as potency, stability, or receptor affinity. Researchers create analogs to explore structure–activity relationships, optimize drug candidates, or investigate how particular features influence behavior, while preserving the core features that drive activity.

In biology, analogous structures are features that serve similar purposes in different species but evolved independently. This results from convergent evolution rather than shared ancestry. Classic examples include the wings of birds and insects, which perform the same function but have different developmental origins. Analogy is distinguished from homology, where similarity reflects common ancestry.

In technology, analog (or analogue) commonly refers to continuous signals and devices that process them, in contrast with digital systems. Analog signals vary smoothly over time and are used in audio, sensing, and instrumentation. The term analoger appears in non-English texts to describe such continuous phenomena or components.

See also: analogue versus digital; homologous and analogous structures; convergent evolution; analog computer.