Nobel Prize physicist from Germany (6)
I believe the answer is:
planck
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">nobel prize physicist from germany</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for planck that I've seen before include "German physicist giving name to a constant" , "Max ---, quantum theorist" , "German physicist, initiator of quantum theory, d. 1947" , "Max --, German scientist, gave name to a constant" .)