Detente comes from the French word, loosen or relax.
Within the context of history, the word has been used notably during the Cold War period of the 20th Century. Richard Nixon, president of the United States and his Secretary of State, Henry Kissenger began a period of easing the strained relations between the West and East (Soviet Union) during the 1970s.
To this point, this was a major foreign policy shift of the United States. Since the end of World War II, the foreign policy of the US and its allies had been one of Containment towards the Soviet Union and its allies. The idea of detente was a concession by Nixon and Kissenger that Containment had failed.
There were other periods of detente throughout European history. During the 19th Century Napoleonic Wars, detente between Czarist Russia and Austria for example or Sweden and Prussia during the same period. Finally, also during the 18th Century the easing of tensions between Spain and Portugal.
There are other examples, but I believe the intent of your question has been answered in my first part.
Hope it helps.
The English word detente means easing of strained relations. This word is used particularly in respect to relations between nations aor major political groups. One popular a use of this term in recent years has been to describe the development of friendlier relations between communist and non-communist countries as with loosening of Cold War alliances and easing of tension in 1070's. In these developments the United States, Canada, Japan, and several other allies, sent diplomats to China, and China Joined the UN in 1971. In 1972, the USSR and the USA signed agreements to limit nuclear arms folllowing a series of meetings called the Strategic Arms Limitation Talks (SALT). This detente helped increase business, cultural and diplomatic exchanges between these countries.