One before tee (3)
I believe the answer is:
ess
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">one before tee</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 ess that I've seen before include "Letter from Mid-West" , "Alphabet letter" , "Nineteenth letter" , "top secret" , "Curvaceous letter" .)