po

Noun (4)

1. a radioactive metallic element that is similar to tellurium and bismuth; occurs in uranium ores but can be produced by bombarding bismuth with neutrons in a nuclear reactorSynonyms: poloniumPoatomic number 84
2. a noncommissioned officer in the Navy or Coast Guard with a rank comparable to sergeant in the ArmySynonyms: petty officerPOP.O.
3. a European river; flows into the Adriatic SeaSynonyms: PoPo River
4. an independent agency of the federal government responsible for mail delivery (and sometimes telecommunications) between individuals and businesses in the United StatesSynonyms: United States Post OfficeUS Post OfficePost OfficePO