Basic principles (7)
I believe the answer is:
bedrock
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">basic principles</span>' is the definition.<br/ ><span class="explanation-format__explanation">(bedrock can mean principles something is based on)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for bedrock that I've seen before include "Fundamental principles" , "Basis" , "Fundamental principle" , "Solid foundation" .)