Definition of international trade by different authors:

According to The World Bank, international trade refers to "the exchange of goods, services, and capital across borders." (The World Bank, 2021)

According to the International Trade Administration of the United States, international trade is defined as "the exchange of goods and services between nations. This trade allows countries to specialize in what they do best and to enjoy a greater variety of goods and services." (International Trade Administration, 2021)

In the words of the International Monetary Fund (IMF), international trade refers to the exchange of goods, services, and capital between countries. This exchange is facilitated by the elimination of trade barriers, such as tariffs and quotas, and the promotion of free trade. (Source: International Monetary Fund (IMF). (2017). International trade. IMF)

According to the Cambridge Dictionary, international trade is defined as "the exchange of goods and services between different countries." (Cambridge Dictionary, 2021)

According to the Oxford English Dictionary, international trade refers to "the exchange of goods and services between different countries; commerce between nations." (Oxford English Dictionary, 2021)

According to economist Paul Krugman, international trade is defined as "the exchange of goods and services across national borders." (Krugman, P. R. (1994). The age of diminishing expectations: U.S. economic policy in the 1990s. MIT press)

International trade is defined as the exchange of goods and services across international borders. (Source: Samuelson, P.A. and Nordhaus, W.D. (2010). Economics. McGraw Hill Education, New Delhi)

According to The World Bank, international trade refers to the exchange of goods and services between countries. This trade can take many forms, including the exchange of raw materials, finished goods, and manufactured products. (Source: The World Bank. (2017). International trade. World Bank Group)

According to the International Trade Centre (ITC), international trade is the exchange of goods and services between countries. It involves the transfer of ownership of goods and services from one country to another, either through exports or imports. (Source: International Trade Centre (ITC). (2017). International trade. ITC)

According to the Oxford Dictionary, international trade is defined as the exchange of goods and services between countries. This exchange can take place through trade agreements, trade policies, and trade organizations. (Source: Oxford Dictionary. (2017). International trade. Oxford University Press)

Definition of international trade by different authors

John Danziger (2007) defines international trade as “the exchange of goods and services across national borders.” (Danziger, 2007, p. 3)

James B. Steinberg (2007) states that “International trade is the exchange of goods and services between countries.” (Steinberg, 2007, p. 10)

David Ricardian (1817) explains that “International trade is the exchange of goods and services between countries through the creation of a market for products and services, which allows buyers and sellers to interact with each other and engage in economic exchange.” (Ricardian, 1817, p. 43)

Peter B. Kenen (1969) defines international trade as “the exchange of goods and services between countries, including the exchange of goods and services within multinational corporations, and the exchange of goods and services through international trade organizations.” (Kenen, 1969, p. 73)

Jagdish Bhagwati (2004) defines international trade as “the exchange of goods and services between countries, including the exchange of goods and services within multinational corporations, and the exchange of goods and services through international trade organizations.” (Bhagwati, 2004, p. 8)

Paul Krugman and Maurice Obstfeld (International Economics: Theory and Policy, 2007) define international trade as "the exchange of goods and services among countries."

Richard Baldwin (The Great Convergence: Information Technology and the New Globalization, 2016) defines international trade as "the exchange of goods, services, capital, and technology across borders."

Douglas A. Irwin (Free Trade Under Fire, 2002) defines international trade as "the exchange of goods and services between residents of different countries."

Jagdish Bhagwati (In Defense of Globalization, 2004) defines international trade as "the exchange of goods, services, and factors of production between residents of different countries."

Peter A. G. van Bergeijk (International Trade and the European Union, 2010) defines international trade as "the exchange of goods, services, and intangible assets among countries, including trade in physical and intangible goods, services, and technology."

References:

1. Danziger, J. (2007). International Trade. New York: Routledge.
2. Steinberg, J. B. (2007). The Handbook of International Trade. West Sussex: Wiley-Blackwell.
3. Ricardian, D. (1817). An Essay on the Principles of Political Economy and Taxation. London: John Murray.
4. Kenen, P. B. (1969). The Theory of International Trade. London: Cambridge University Press.
5. Bhagwati, J. (2004). In Defense of Globalization. Oxford: Oxford University Press.
6. Krugman, P. R., & Obstfeld, M. (2007). International Economics: Theory and Policy (8th ed.). New York, NY: Pearson Education, Inc.
7. Baldwin, R. (2016). The Great Convergence: Information Technology and the New Globalization. Cambridge, MA: Harvard University Press.
8. Irwin, D. A. (2002). Free Trade Under Fire (2nd ed.). Princeton, NJ: Princeton University Press.
9. Bhagwati, J. (2004). In Defense of Globalization. Oxford, UK: Oxford University Press.
10. Bergeijk, P. A. G. van. (2010). International Trade and the European Union: Policy and Theory. Cheltenham, UK: Edward Elgar Publishing.