Max Karl Ernst Ludwig Planck was a German physicist and is known for his fundamental contributions to the field of theoretical physics. There are not many synonyms for the name Max Karl Ernst Ludwig Planck, as it is a proper noun and not a common word. However, some synonyms that may be used for Planck's contributions to physics are quantum theory, quantum mechanics, Planck's constant, blackbody radiation, and energy quanta. Planck's work in developing the concept of the quantization of energy and the Planck constant provided a foundation for modern physics, and his name remains synonymous with the field.