Fourth sign of the zodiac (6)
I believe the answer is:
cancer
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">fourth sign of the zodiac</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for cancer that I've seen before include "Crab star sign" , "Fourth sign of the zodiac" , "Sign of the Crab, or a Tropic" , "A Tropic or a malignant disease" , "Zodiac sign of the Crab" .)