Definitions of Einstein:

• noun:   physicist born in Germany who formulated the special theory of relativity and the general theory of relativity; Einstein also proposed that light consists of discrete quantized bundles of energy (later called photons) (1879-1955)
• noun:   someone who has exceptional intellectual ability and originality

  Example: "He's smart but he's no Einstein"

• name:  A surname (very rare: popularity rank in the U.S.: #29058)