Bidding(Bid) is an offer (often competitive) of setting a price one is willing to pay for something [I]or a demand that something be done. A price offer is called a bid. The term may be used in context of auctions.
[/I]A lot number is an identification number assigned to a particular quantity or lot of material from a single manufacturer. Lot numbers can typically be found on the outside of packaging. For cars, the same thing is called a Vehicle Identification Number.