It may be below a crest (5)
I believe the answer is:
motto
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">it may be below a crest</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 motto that I've seen before include "Catchphrase" , "Phrase in a Christmas cracker" , "Phrase to express character" , "Recurring musical phrase" , "(Family) maxim" .)