Rzeczpospolita (pronounced [ʐɛt͡ʂpɔsˈpɔlita] ^ⓘ) is a traditional Polish term for a political community founded for the common good. The noun "rzeczpospolita", meaning "public welfare, general good or advantage" rzecz "thing, matter" and pospolita "common", is analogous to the Latin rēs pūblica (rēs "thing" + pūblica "public, common"), i.e. republic, in English also rendered as commonwealth, for example, the Polish-Lithuanian Commonwealth. The modern term in English is republic and refers to all modern republics, for instance the French Republic. In modern Polish, the word rzeczpospolita is used exclusively in relation to the Republic of Poland, while any other republic is referred to in Polish as a republika (e.g. Italian Republic – Republika Włoska).

The term rzeczpospolita has been used in Poland since the beginning of the 16th century. It was adapted for Poland, as it at that time had a unique republican system, similar to the former Roman rés pública. The famous quote by Jan Zamoyski, the Lord Chancellor of the Crown, on the importance of education is an example of its use:

Takie będą Rzeczypospolite, jakie ich młodzieży chowanie.

Such will be the Commonwealths as the upbringing of their youth.

— Jan Zamoyski, Foundation Act of the Academy of Zamość; 1600

The meaning of rzeczpospolita is well described by the term commonwealth. As a result, the literal meaning of Rzeczpospolita Polska is "Polish Commonwealth", or "Republic of Poland". Although the first Rzeczpospolita was an elective monarchy, the king had no real power, as most of the state affairs were regulated by the parliament and senate, known as the Sejm.

The Latin name for the Polish-Lithuanian Commonwealth is Rés Pública Poloniae.^{[citation needed]}

Rzeczpospolita is also used in a series of symbolic names referring to three periods in the history of Poland: