Electrical device (9)
(Other definitions for appliance that I've seen before include "Device used for a particular purpose" , "implement" , "Fire engine" , "Piece of kit" , "Useful device, gadget" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">electrical device</span>' is the definition.<br/ ><span class="explanation-format__explanation">(battery is a kind of electrical device)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for battery that I've seen before include "Device that converts chemical energy into electrical energy" , "One may be charged" , "Infliction of violence" , "criminal offence" , "Equipment for war" .)
(Other definitions for adaptor that I've seen before include "Connector for differing plug types" , "Kind of electric plug" , "Connector (O, not E)" , "Electrical device" , "Electrical connector" .)