Homology is a concept in biology that refers to the similarity between different organisms or structures due to shared ancestry. It is the study of similar traits or characteristics in different species that are the result of common evolutionary origins. Homology is used to infer relationships between organisms and to understand the evolutionary history of traits or structures. By comparing homologous features, researchers can determine how organisms are related and how they have evolved over time. Homology is a fundamental concept in evolutionary biology and plays a key role in the study of phylogenetics and comparative anatomy.