Noun has 4 senses

• po(n = noun.substance) atomic number 84, polonium - 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;


• po(n = noun.person) p.o., petty officer - a noncommissioned officer in the Navy or Coast Guard with a rank comparable to sergeant in the Army;



• po(n = noun.object) po river - a European river; flows into the Adriatic Sea;



• po(n = noun.group) post office, united states post office, us post office - an independent agency of the federal government responsible for mail delivery (and sometimes telecommunications) between individuals and businesses in the United States;