‘异伦’ literally combines ‘异’ (yì), meaning ‘different,’ ‘unusual,’ or ‘deviant,’ and ‘伦’ (lún), meaning ‘kind,’ ‘category,’ or ‘order’—often used in classical Chinese to refer to natural or moral categories, especially in relationships among beings. Together, 异伦 describes a relationship that crosses natural or socially accepted boundaries—most commonly between species, such as human–animal pairings—which is viewed as unnatural, improper, or morally transgressive in traditional Chinese thought.

The term carries strong negative connotations and appears primarily in classical texts, literary criticism, or modern discourse discussing ethics, biology, or social norms. It is rarely used in casual speech but may surface in academic, philosophical, or satirical contexts to highlight boundary violations. Unlike neutral terms like ‘跨类’ (cross-category), 异伦 inherently implies moral or natural deviation—not just difference—and often evokes disapproval or caution.