Why is the killing of American Indians by European colonists and explorers between the 15th and 19th centuries considered genocide?

The killing of American Indians by European colonists and explorers is considered genocide because it involved the deliberate and systematic destruction of indigenous populations, including massacres, displacement, forced assimilation, and the spreading of diseases. These actions aimed to annihilate or remove indigenous peoples from their lands, leading to a significant decline in their populations and cultures.