Large vehicle (3)
(Other definitions for van that I've seen before include "Commercial vehicle at head of army" , "Forefront as of an army" , "Commercial road vehicle" , "camper?" , "Commercial vehicle in the lead?" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">large vehicle</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for bus that I've seen before include "Public service vehicle" , "Public transport vehicle" , "eg Double-decker" , "Use transport" , "Mode of public transport" .)
(Other definitions for truck that I've seen before include "Bargain" , "See 14" , "Exchange" , "Goods vehicle" , "Large road vehicle" .)