From Longman Dictionary of Contemporary Englishgavelgav‧el /ˈɡævəl/ noun [countable] 
SBBTa small hammer that the person in charge of a meeting, court of law, auction etc hits on a table in order to get people’s attention
SBBTa small hammer that the person in charge of a meeting, court of law, auction etc hits on a table in order to get people’s attentionExamples from the Corpus
gavel• Using the butt of a pistol as a gavel Rayne began the auction.• Then he banged a gavel to pronounce them married and they all kissed, to wild applause from the gallery.• The big gavel of term limits has come down hard.• So which party will voters see when the final gavel closes the convention tomorrow night?• The new jacket, with its swinging gavel and bold lettering, looks like a John Grisham thriller.• Maitre Tajan will be bringing the gavel down on two attractive paintings from the Polo collection in this sale of Old Masters.• The new Senate president banged down the gavel and called the chamber to order with a strong firm voice.• Already the auctioneer was positioned outside on the lawn, a table before him and a wooden gavel in his hand. 