| Noun | 1. | DoI - the United States federal department charged with conservation and the development of natural resources; created in 1849executive department - a federal department in the executive branch of the government of the United States FWS, United States Fish and Wildlife Service, US Fish and Wildlife Service - an agency in the Department of the Interior that conserves and protects fish and wildlife and their habitats; assesses the environmental impact of pesticides and nuclear power site and hydroelectric dams and thermal pollution National Park Service - an agency of the Interior Department responsible for the national parks |