Imperialism can best be describes as the creation of an unequal relationship between two states. It can take many different forms and is usually the result of the establishment of an empire.
One common form of imperialism is economical. This practice can best be illustrated by understanding the actions of European nations in the 19th and 20th centuries. During this time, European countries participated in imperialistic practices as they sought to strengthen their empires and nations. This resulted in unequal territorial and economic relationships between the Europeans and the inhabitants of the areas they dominated. It can be beneficial in some ways, such as the building up of infrastructure of technological exchanges that take place, but many historians usually view it as a one-sided relationship in terms of the benefits. While it is true that India saw its infrastructure modernized under British rule, it was also robbed of huge amounts of valuable raw materials wealth.
Cultural imperialism in slightly different. Cultural imperialism refers to when one nation or people force beliefs on another that are different than their own. One example would be the missionary efforts of the Spanish in the Americans after the conquests of Cortez and Pizzaro. Catholic monks forced natives to convert, disrupting their own beliefs and replacing traditional structures. In this example, the results were disastrous, but there are some cases where it could also be beneficial. When Mughal emperor Akbar took power in India he banned the practice of Sati, or bride burning, which today we view as a positive move but which was definitely cultural imperialism.