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 reactor

[ Syn: polonium , po , atomic number 84 ]

a noncommissioned officer in the Navy or Coast Guard with a rank comparable to sergeant in the Army

[ Syn: petty officer , po , p.o. ]

a European river; flows into the Adriatic Sea

[ Syn: po , po river ]

an independent agency of the federal government responsible for mail delivery (and sometimes telecommunications) between individuals and businesses in the United States

[ Syn: united states post office , us post office , post office , po ]