bidder UK /ˈbɪd.ə/US /ˈbɪ.dɚ/ noun4 •Someone who bids (all senses), but most commonly, one offers to pay a specified price at an auction.The highest bidder shall get the house. •One who commands or orders. •(old-fashioned, rare) One who asks or invites. •(no longer used) One who begs. formsbidders