perestroika

noun

1. (historical, uncountable)A program of political and economic reform carried out in the Soviet Union in the 1980s and early 1990s under the leadership of Mikhail Gorbachev.

   “Gorbachev would introduce glasnost (openness and freedom) and perestroika (economic restructuring) to Russia under his tenure, ultimately freeing thousands of political prisoners and dissidents and trying to address the shortages in food and goods that had become the hallmarks of the failing Soviet economy.”

   “[Gorbachev] did not champion perestroika and glasnost alone; much of the nomenklatura had decided that the Soviet economic and social model was dysfunctional, corrupt and endemically inefficient and had to change.”

2. (historical, uncountable)The period of time in the Soviet Union during which these reforms were carried out and in effect.
3. (countable)A situation where a small variation of parameters leads to a sudden change in properties.