"Much obliged!"
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">much obliged</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for thank you that I've seen before include "Words of acknowledgement" , "Conventional expression of gratitude" , "Cheers" , "Ta" , "I'm grateful" .)