Wetlands.
(iv) Wetlands. The term wetlands means those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas.
Source
40 CFR § 117.1
Scoping language
As used in this part, all terms shall have the meanings stated in 40 CFR part 116.