Nautical marker (4)
I believe the answer is:
buoy
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">nautical marker</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 buoy that I've seen before include "Navigational marker" , "Distinctive float fixed to seabed" , "To raise" , "dolphin" , "Coloured float" .)