Volcano's output (4)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">volcano's output</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for lava that I've seen before include "Volcanic outflow" , "Discharge from volcano" , "Volcanic flowing substance" , "Hot molten rock" , "It flows from volcano" .)