Know Open Door Policy, Roosevelt Corollary, Dollar Diplomacy, Big Stick Diplomacy.

1. Open Door Policy: The Open Door Policy was a concept introduced by the United States in the late 19th and early 20th centuries. It aimed to promote equal access to trade and investment opportunities in China. The policy called for all nations to have equal trading rights with China, while also respecting China's territorial integrity and preserving its independence. It was primarily concerned with preventing the colonization or division of China by foreign powers.

2. Roosevelt Corollary: The Roosevelt Corollary was an addition to the Monroe Doctrine articulated by President Theodore Roosevelt in 1904. It stated that the United States had the right to intervene in the affairs of Latin American countries to restore order and stability. It was seen as an extension of the Monroe Doctrine, which aimed to prevent European colonization in the Americas, but the Roosevelt Corollary widened the scope to justify American intervention to protect its economic interests in the region.

3. Dollar Diplomacy: Dollar Diplomacy was a foreign policy approach introduced by President William Howard Taft in the early 20th century. It aimed to extend American influence and protect American economic interests in foreign countries, particularly in Latin America and East Asia. The policy involved using American investment and financial power as a means of exerting political influence and establishing economic dominance. It often involved offering financial assistance to governments in exchange for political favors or the protection of American business interests.

4. Big Stick Diplomacy: Big Stick Diplomacy, also known as the Rooseveltian Diplomacy, was a foreign policy approach associated with President Theodore Roosevelt. The term comes from the saying "speak softly and carry a big stick," which symbolized the need for diplomatic negotiations backed by a strong military capability. The policy emphasized the use of military force as a means of safeguarding American interests and promoting stability in the Western Hemisphere. It was showcased in actions such as the Panama Canal negotiations and Roosevelt's intervention in the Russo-Japanese War.