The moose (North America) or Eurasian elk (Europe) (Alces alces) is the largest extant species in the deer family. Moose are distinguished by the palmate antlers of the males; other members of the family have antlers with a dendritic ("twig-like") configuration. Moose typically inhabit boreal and mixed deciduous forests of the Northern Hemisphere in temperate to subarctic climates. Moose used to have a much wider range but hunting and other human activities greatly reduced it over the years. Moose have been reintroduced to some of their former habitats. Currently, most moose are found in Canada, Alaska, Scandinavia and Russia. Their diet consists of both terrestrial and aquatic vegetation. The most common moose predators are wolves, bears, and humans. Unlike most other deer species, moose are solitary animals and do not form herds. Although generally slow-moving and sedentary, moose can become aggressive and move surprisingly quickly if angered or startled. Their mating season in the autumn can lead to spectacular fights between males competing for the right to mate with a particular female.

The animal bearing the scientific name Alces alces is known in Britain as the "elk",[2] and in North America as the "moose".

The British English word "elk" has cognates in other Indo-European languages, for example elg in Danish / Norwegian; älg in Swedish; Elch in German; and łoś in Polish (Latin alcē or alcēs and Greek ἅλκη álkē are probably Germanic loanwords).[3] Confusingly, the word "elk" is used in North America to refer to a different animal, the elk (or, less commonly, the "wapiti", Cervus canadensis), which is a similar though slightly smaller species (the second-largest deer species) and behaviorally and genetically divergent from the smaller red deer of central and western Europe. Presumably, early European explorers in North America called this species "elk" due to its size and, as people coming from the British Isles, they would have had no opportunity to see the difference between a member of the genus Cervus and an animal fitting the description of Alces back in Europe, absent there during the 17th and 18th centuries.