| A | B |
| Alamo | a mission in San Antonio, Texas where Texans, in their struggle to gain independence from Mexico, lost a battle in 1836 against a much larger Mexican force. |
| annex | to add on, to add territory onto a nation. |
| electorate | those who elect. |
| Forty-niners | people who were part of the "gold rush" to California after gold was discovered there in 1848. |
| Manifest Destiny | a belief held by many during the 1840s that the U.S. was destined to expand to the Pacific Ocean. |
| Mexican Cession | land bought from Mexico (as part of the treaty ending the Mexican War in 1848) which included areas now known as the states of California, Nevada, Utah, and most of Arizona and New Mexico. |
| Monroe Doctrine | a declaration by President Monroe stating that the U.S. opposed further colonization of the American continents and that the U.S. would continue its policy of neutrality toward Europe. |
| nationalism | strong feeling of pride and loyalty toward one's nation. |
| Ostend Manifesto (1854) | a memorandum sent by three American diplomats to Spain telling it that the U.S. had the right to seize Cuba unless Spain sold it to the U.S. (The manifesto did not receive President Pierce's support and was repudiated.) |
| Wilmot Proviso (1848) | a proposal (never enacted) which would have banned slavery in any territory the U.S. acquired as a result of the Mexican War. |
| "54 40 of Fight" | Campaign slogan of James K. Polk which referred to his believe that the Oregon Country belonged to the US.Therefore the boundaries should be 54 degrees 40 minutes of north latitude. |
| Gadsden Purchase | area of southern Arizona purchased from Mexican after the Mexican War for railroad land. |
| Winfield Scott | American general during the Mexican War who defeated the Mexicans at Vera Cruz. Also known as "Old Fuss and Feathers". |
| Zachary Taylor | American general during the Mexican War who defeated the Mexicans at Mexico City. Also known as "Old Rough and Ready". |
| Treaty of Guadalupe Hidalgo | Ended the Mexican War granting the US the Mexican Cession territory. |
| William Walker | Led revolt in Nicaragua in an attempt to make the region a part of the United States. |
| Pan American Conference | Proposed by the United States but not attended by American representatives because the issue of slavery was discussed. |
| John L. O'Sullivan | Created the phrase "Manifest Destiny" in his Boston newspaper. |