To a modern biologist, a vole is quite distinct from a (true) mouse. But in colloquial use the distinction is not as clear. The biologists borrowed the term "vole" and then applied it consistently to various members of Arvicolinae, the voles muskrats and lemmings, which is a different family within the rodents to true mice. But orginally the colloquial term "vole" meant "field mouse", which are examples of true mice. (The most common field mouse, often colloquially called as such, in Britain is called by biologists the wood mouse; the yellow-necked mouse is also a field mouse). And the three voles found on the British mainland today (bank vole, field or short-tailed vole, and water vole), originally had other common names.