Caviar base (3)
I believe the answer is:
roe
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">caviar base</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for roe that I've seen before include "Caviar" , "Swift runner" , "Mass of fish's eggs" , "Fish eggs; small deer" , "Part of fish, sounds like go through water" .)