'Deer' once meant any animal — German 'Tier' still does. It narrowed after the Norman Conquest.
A hoofed grazing or browsing animal, typically with antlers borne by the male, belonging to the family Cervidae.
From Old English 'dēor' (animal, beast — any wild animal whatsoever), from Proto-Germanic *deuzą (animal), from PIE *dʰeus- (to breathe, to blow — that which breathes, a living creature). The word originally meant any animal at all, not specifically a cervid. German 'Tier' (animal) preserves the original broad
'Deer' once meant any animal — the same word as German 'Tier' (animal). Shakespeare still occasionally used 'deer' in the broader sense. The word narrowed to mean only cervids because after the Norman Conquest, deer-hunting became the defining aristocratic activity of the English nobility, and 'deer' (the animal you hunted) became so closely associated with the hunt that it lost its general meaning. 'Wilderness