1. (noun) 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

• atomic number 84
• polonium

2. (noun) a noncommissioned officer in the Navy or Coast Guard with a rank comparable to sergeant in the Army

• p.o.
• petty officer

3. (noun) a European river; flows into the Adriatic Sea

• po river

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

• post office
• united states post office
• us post office

1. (noun) 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

• metal
• metallic element

2. (noun) a noncommissioned officer in the Navy or Coast Guard with a rank comparable to sergeant in the Army

• enlisted officer
• noncom
• noncommissioned officer

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

• independent agency

1. (noun) a noncommissioned officer in the Navy or Coast Guard with a rank comparable to sergeant in the Army

• master-at-arms
• scpo
• senior chief petty officer