fisher

Fisher is a surname of English origin and is borne by many individuals across fields such as science, arts, and public life. Among the most influential is Ronald Aylmer Fisher (1890–1962), an English statistician, geneticist, and naturalist whose work helped found modern statistical science. His contributions include the development of analysis of variance and maximum likelihood estimation, and the formal concept of information in statistics. Several statistical methods bear his name, such as Fisher's exact test, Fisher information, and Fisher's linear discriminant.

The term also refers to a person who fishes, though in contemporary usage the more common term is fisherman or fisherwoman.

In biology, the fisher (Pekania pennanti) is a carnivorous mammal of the mustelid family native to North American forests. It is larger than a weasel, has a long, dark-brown coat, and inhabits wooded areas where it hunts small to medium-sized prey and occasionally consumes fish. The species has several subspecies and a range that includes parts of Canada and the United States; its habitat has been subject to loss and fragmentation, impacting regional populations and conservation efforts.

Fisher-related terms extend into statistics and data analysis, including Fisher information, which quantifies how much information an observed variable provides about an unknown parameter, and Fisher's exact test, used for small-sample contingency table analyses. The name also appears in place names, organizations, and cultural contexts, reflecting its broad resonance in language and scholarship.