Simple chord (5)
I believe the answer is:
triad
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">simple chord</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 triad that I've seen before include "three making a sound?" , "Set of three; chord" , "Chinese secret society" , "Group or set of three" , "Could be major" .)