Cultural imperialism is when one country or group of people impose their cultural standards (in art, politics, philosophy, etc.) on another country or group. In general, most imperialism implies and involves cultural imperialism, however, cultural imperialism can occur in many other ways, such as during international commerce. One example would be one group expecting another to conduct all business in the first group's language.
The Soviet Union promoted cultural imperialism in all the countries that fell under its influence.