Cranberries are a group of evergreen dwarf shrubs or trailing vines in the subgenus Oxycoccus of the genus Vaccinium. In Britain, cranberry may refer to the native species Vaccinium oxycoccos, while in North America, cranberry may refer to Vaccinium macrocarpon. Vaccinium oxycoccos is cultivated in central and northern Europe, while Vaccinium macrocarpon is cultivated throughout the northern United States, Canada and Chile. In some methods of classification, Oxycoccus is regarded as a genus in its own right. Cranberries can be found in acidic bogs throughout the cooler regions of the Northern Hemisphere.

The term subshrub or undershrub refers to either a small shrub or a perennial that is largely herbaceous but slightly woody at the base. "Subshrub" is often used interchangeably with "bush".