The term slough (pronounced "slew") has several meanings related to wetland or aquatic features that seem to derive from local experience. For example:
  • In eastern and southeastern United States, a slough is a type of swamp or shallow lake system, typically formed as or by the backwater of a larger waterway. It is similar to a bayou with trees being present (that is, a swamp), and unlike a bog or marsh that lacks trees.

  • In western U.S., a slough is a secondary channel of a river delta. While this is in essence the same application of the term as in the eastern U.S., the main difference is that there are no native trees in the west that would grow out into the waterway to form a swamp.

  • In coastal California, a slough is a narrow channel in a shallow salt-water marsh, usually flushed by the tide.