Publicly nude
Publicly nude means nude in any place where a person may be observed by another person. Any person is nude if the person has failed to cover the rectal area, pubic area or genitals. A female person is also nude if she has failed to cover both breasts below a point immediately above the top of the areola. Each such covering must be fully opaque. No person under the age of 10 years shall be considered publicly nude.
Source
36 CFR § 261.2
Scoping language
The following definitions apply to this part: