What does "basin" mean?

Additional senses

1. 2.A hollow vessel, of various forms and materials, used in the arts or manufactures, as that used by glass grinders for forming concave glasses, by hatters for molding a hat into shape, etc.
2. 3.A hollow place containing water, as a pond, a dock for ships, a little bay.
3. 4.(Physical Geog.) (a) A circular or oval valley, or depression of the surface of the ground, the lowest part of which is generally occupied by a lake, or traversed by a river. (b) The entire tract of country drained by a river, or sloping towards a sea or lake.
4. 5.(Geol.) An isolated or circumscribed formation, particularly where the strata dip inward, on all sides, toward a center; -- especially applied to the coal formations, called coal basins or coal fields.