Valentine's Day flower (4)
I believe the answer is:
rose
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">valentine's day flower</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 rose that I've seen before include "'A . . . . by any other name smells as sweet'" , "vacated bed" , "Prickly shrub with bright flowers" , "18 [ROSE]" , "Stood" .)