Lighter fuel (6)
(Other definitions for propane that I've seen before include "Type of gas" , "Bottle gas" , "A hydrocarbon gas" , "Gas used as fuel" , "Bottled fuel gas" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">lighter 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 butane that I've seen before include "Inflammable gas produced from petrol" , "Bottled gas used as a fuel" , "Lighter fuel" , "Flammable gas in petroleum" .)