Fossil fuel (4)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">fossil fuel</span>' is the definition.<br/ ><span class="explanation-format__explanation">(gas is a fossil fuel)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for gas that I've seen before include "Empty talk (colloq.)" , "Hydrogen possibly" , "Hydrogen or methane, say" , "Oxygen maybe" , "See 2" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">fossil fuel</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 oil that I've seen before include "Fluid lubricant" , "eg Olive" , "Lubricant or petroleum" , "Lubricating liquid" , "Valuable viscous liquid" .)
(Other definitions for peat that I've seen before include "Partially carbonised vegetable matter used as a fuel when dried" , "Fuel from bogs" , "Fuel from marsh" , "Bog material" , "Natural solid fuel" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">fossil fuel</span>' is the definition.<br/ ><span class="explanation-format__explanation">(coal is a kind of fossil fuel)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for coal that I've seen before include "Fossil fuel" , "Carbonaceous rock used as fuel" , "This consists mainly of carbon" , "slack" , "Solid fuel" .)