| Term | Definition |
| Red Scare | Fear of Americans during the Cold War that there were communists everywhere out to destroy U.S. |
| Alger Hiss | Former State Dept Official found guilty of spying for Soviet Union. Sentenced 5 years in prison in 1950. Prompts fear of communists in Government. |
| Rosenbergs | Ethel and Julius were convicted of passing atomic secrets to Soviets. Executed in 1953. |
| Loyalty Boards | Boards that tested the loyalty of government workers. Forces 3000 to resign. |
| HUAC | House Un-American Activities Committee investigate actors, directors, and writers for suspected communist ties. Ruin many people's careers. |
| McCarthyism | Senator Joseph McCarthy launched a campaign to uncover suspected communists without any real evidence. Many Americans lost their jobs and reputations. |