united states post office: an independent agency of the federal government responsible for mail delivery (and sometimes telecommunications) between individuals and businesses in the United States
independent agency: an agency of the United States government that is created by an act of Congress and is independent of the executive departments
urge incontinence: urinary incontinence that is generally attributable to involuntary contracts of the bladder muscle resulting in an urgent need to urinate accompanied by a sudden loss of urine; most common in people over 60 years of age