Long note (5)
I believe the answer is:
breve
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">long note</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for breve that I've seen before include "(In music) long note" , "Note with the time value of eight crotchets" , "Accent - musical note" , "Rarely used musical note" , "Long note (mus.)" .)