Drinking glasses (8)
I believe the answer is:
tumblers
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">drinking glasses</span>' is the definition.<br/ ><span class="explanation-format__explanation">(tumbler is a kind of drinking glass)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for tumblers that I've seen before include "Acrobats and drinking vessels" , "gymnasts" , "circus acts?" , "Pigeons" , "Flat bottomed glasses" .)