Software test stage (4)
I believe the answer is:
beta
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">software test stage</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 beta that I've seen before include "Character between alpha and gamma" , "character in Marathon" , "Old character" , "Greek character - not quite top-notch" , "In a constellation, a star second in brightness" .)