Final answer:
While specific nicknames for Albert Einstein aren't well-documented, his surname has become a popular euphemism for high intelligence in American culture, often used colloquially to describe someone extremely smart.
Step-by-step explanation:
Albert Einstein was recognized as much for his unique character as for his revolutionary theories in physics. Although his vast intellectual contributions to science earned him the reputation as a symbol of genius, specific nicknames for Einstein by the American people aren't well documented in historical texts. Instead, his last name, Einstein, has become synonymous with extraordinary intelligence and is colloquially used to refer to someone exceptionally smart. For instance, calling someone an 'Einstein' is a way to comment on their intellectual prowess. The association of Einstein with towering intellect is entrenched in popular culture, further solidified by his contributions, like the letter to President Roosevelt which highlighted the potential for nuclear weapons and helped spur the U.S. government into action.