Orthology

Part of speech: noun

Definitions

1. A biological principle describing the similarity of function in structures, a linguistic notion about equivalent meanings in distinct languages, and a concept referring to the appropriate organization of traits among species exemplify this term
2. A concept identifying genes or features in different species that originated from a common ancestor ; the practice of using language according to established rules and standards
3. The condition where genetic sequences or anatomical traits in separate organisms correspond due to shared origin ; adherence to proper and accepted language forms

Etymology: "Orthology" is a plain compound built from two Greek elements. "Ortho-" comes from Greek "orthos", meaning straight, correct or right, and "-logy" comes from "logos", meaning word, study or discourse. Put together, the term means something like the study of what is correct, though in its modern uses it has been applied to the correspondence between things rather than to any study of correctness. Its biological sense is the most established. Here "orthology" names the relationship between genes in different species that descend from a single ancestral gene through speciation, so that they usually keep the same function. The linguistic and organizational senses listed in the meaning draw on the same idea of correspondence: a counterpart that is "straight" across a boundary, whether between species, languages or traits.