| Term | Definition |
| South Pass | path discovered by Jedediah Smith that allowed for safer passage through the Rocky Mountains to get to the Oregon Territory |
| diplomacy | the art of conducting negotiations with other countries |
| $15 million | price tag of the Louisiana Purchase |
| Tejanos | Texans of Mexican descent |
| "Remember the Alamo!" | battle cry of the Texas War for Independence |
| Treaty of Guadalupe Hidalgo | Mexico agreed to give up half of its territory in exchange for $15 million from the United States and promises of protection of Mexicans living in Texas |
| Lewis & Clark | original explorers of the Oregon Territory |
| Lone Star Republic | nickname for the Republic of Texas |
| Stephen F. Austin | son of Spanish business owner who dreamed of starting a U.S. colony in Spanish Texas |
| Florida | territory that was yielded to the United States in exchange for $5 million in settlers' claims and honoring Spain's claims to Texas |
| The Alamo | Americans in Texas rebelled against the Mexican government in which an incident in a Spanish mission that turned into a bloody battle where all Texans who fought there were killed |
| Spain | European country who first colonized Florida in the 1500s |
| Napoleon | French leader who offered to sell the entire Louisiana Territory to the United States |
| Santa Anna | head of Mexican government |
| Mexican-American War | the war with Mexico from 1846 to 1847 that resulted in Mexico ceding to the United States a huge region from Texas to California |
| Manifest Destiny | belief that it was America's right and duty to spread the nation across the North American continent from coast to coast |
| Rio Grande River | river that Texas claimed as its border with Mexico |
| Russia, Spain, Britain, and United States | four countries that claimed the Oregon Territory |
| Mexican Cession | present-day states of California, Nevada, Utah, Arizona, New Mexico and parts of Colorado and Wyoming |
| Texas War for Independence | the 1836 rebellion of Texans against Mexican rule that resulted in Texas becoming an independent nation |
| Thomas Jefferson | president who purchased the Louisiana Territory |
| 10 years | how long Texas was an independent country for |
| Sam Houston | commander of the Texas revolutionary army |
