A bidder is someone who offers to pay a certain amount of money for something that is being sold. If you sell something to the highest bidder, you sell it to the person who offers the most money for it. The sale will be made to the highest bidder subject to a reserve price being attained.

Is bidder the buyer?

A bid price is the highest price that a buyer (i.e., bidder) is willing to pay for a goods. It is usually referred to simply as the "bid".

What does Bidding mean?

noun. an order; command (often in the phrases do or follow the bidding of, at someone's bidding) an invitation; summons. the act of making bids, as at an auction or in bridge. bridge a group of bids considered collectively, esp those made on a particular deal.