noun

• Albert Einstein, the world-famous 20th-century theoretical physicist who developed the theory of relativity.
• A surname from German.
• (sometimes sarcastic) An extremely clever or intelligent person.
• (photochemistry, dated) One mole of photons, regardless of frequency, as used to measure irradiance.
• (informal) A genius; a very smart person.
• (by extension, informal, sarcastic) An idiot; a very stupid person.
• (mathematics, physics) A shape that can be repeated to cover a plane with a nonrepeating pattern.