pO

Po is a term with several distinct meanings across science, geography, and culture. In science, it most often refers to the element polonium. In geography, it denotes the Po River in northern Italy. In popular culture, Po is the name of the panda protagonist in the Kung Fu Panda film series.

Polonium, symbol Po, is a rare radioactive element with atomic number 84 that was discovered in 1898 by Marie and Pierre Curie. It occurs in trace amounts in uranium ores and is produced commercially in nuclear reactors. Polonium has several isotopes, the most persistent being Po-210, which has a half-life of about 138 days. It is highly toxic and radioactive, requiring stringent handling precautions. Uses have been historically limited and specialized, including small heat sources and static-elimination devices, though its notoriety is largely tied to its potential for poisoning. The poisoning of former Russian intelligence officer Alexander Litvinenko in 2006 brought polonium into public attention and raised concerns about illicit access to radioactive materials.

The Po River is the longest river in Italy, running roughly 652 kilometers (405 miles) from the Cottian Alps in the northwest across the Po Valley to the Adriatic Sea. It passes through several major cities and supports irrigation, hydroelectric power, and industrial activity in the region. The river basin has been a key agricultural area since ancient times and remains central to regional economics and ecology.

In popular culture, Po is the title character of the Kung Fu Panda franchise. Portrayed as a clumsy but gifted panda, Po trains to become a kung fu master and serves as the Dragon Warrior in the films and related media. The character is voiced by Jack Black in most English-language productions.

PO can also stand for post office, purchase order, or petty officer in various contexts.