(a) National Forest Wilderness means an area or part of an area of national forest lands designated by the Wilderness Act or by a subsequent act of Congress as a wilderness area.

(b) National Park System means all federally owned or controlled areas administered by the Secretary through the National Park Service.

(c) National Wilderness Preservation System means the Federally owned areas designated by the Wilderness Act or subsequent acts of Congress as wilderness areas.

(d) National Wildlife Refuge System means those lands and waters administered by the Secretary as wildlife refuges, wildlife ranges, game ranges, wildlife management areas, and waterfowl production areas established under any statute, proclamation, executive order, or public land order.

(e) Roadless area means a reasonably compact area of undeveloped Federal land which possesses the general characteristics of a wilderness and within which there is no improved road that is suitable for public travel by means of four-wheeled, motorized vehicles intended primarily for highway use.

(f) Roadless island means a roadless area that is surrounded by permanent waters or that is markedly distinguished from surrounding lands by topographical or ecological features such as precipices, canyons, thickets, or swamps.

(g) Secretary means the Secretary of the Interior or an official of the Department of the Interior who exercises authority delegated by the Secretary of the Interior.

(h) Wilderness means a wilderness as defined in section 2(c) of the Wilderness Act.