Ermine, name given to various species of weasel, particularly during the winter season, when the fur of individuals inhabiting colder latitudes is white. The name is applied especially to the stoat, which inhabits temperate and subarctic regions of Europe, North America, and Asia. Various related species of ermine live in North America, including the long-tailed weasel and the least weasel. At one time only high-ranking members of the nobility were permitted to wear ermine pelts; later such pelts became a part of the insignia of important judicial officials. Today ermine's popularity has declined.

Scientific classification: Ermine belong to the family Mustelidae. The stoat is classified as Mustela erminea, the long-tailed weasel as Mustela frenata, and the least weasel as Mustela nivalis.