The word parity comes from the Latin paritas - equality. In a general sense, it means equality of phenomena, equality of groups. However, the term is used in politics and economics with slightly different meanings.
Gold parity is a fixed content of pure gold in a unit of national currency. Gold parity is also understood as the ratio of currencies based on their gold content. The more gold a country's monetary unit contains, the more units of another currency it can be exchanged. The term "purchasing power parity" is also used - the ratio of the purchasing power of currencies to a certain set of goods and services. This model can function successfully only with the free movement of capital, goods and services across borders. The higher the customs duties, transportation costs and legal restrictions on exports and imports, the less can be purchased for a certain amount of money. Accordingly, the more the exchange rate deviates from the established purchasing power parity. Currency parity is the statutory ratio of two currencies. It is assumed that at currency parity, an equilibrium is achieved between supply and demand when exchanging one currency for another. It is established on the basis of the official content in the monetary unit of gold, or the conventional currency issued by the IMF - SDR (Special Drawing Rights), or one of the hard world currencies. Strategic parity is a state of international relations in which victory is equally likely for all parties to a potential military conflict. This condition also implies that the stronger side is guaranteed to suffer unacceptably high losses in the event of a war. In modern conditions, in the event of a military conflict, third countries will inevitably suffer, so maintaining strategic parity is a common concern. Nuclear parity is an approximate equality of strategic nuclear forces. The situation when the confidence that the enemy is guaranteed to deliver a retaliatory strike is kept from delivering a nuclear strike is called nuclear deterrence.