Taxonomic groups (6)
I believe the answer is:
genera
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">taxonomic groups</span>' is the definition.<br/ ><span class="explanation-format__explanation">(genus is a kind of taxonomic group)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for genera that I've seen before include "Biological groupings" , "Forms" , "Blood vessel" , "Categories making up a family" , "Orders with common characteristics" .)