The Collaborative International Dictionary of English v.0.48:

Auction \Auc"tion\, n. [L. auctio an increasing, a public sale,
   where the price was called out, and the article to be sold
   was adjudged to the last increaser of the price, or the
   highest bidder, fr. L. augere, auctum, to increase. See
   Augment.]
   1. A public sale of property to the highest bidder, esp. by a
      person licensed and authorized for the purpose; a vendue.
      [1913 Webster]

   2. The things sold by auction or put up to auction.
      [1913 Webster]

            Ask you why Phryne the whole auction buys ? --Pope.
      [1913 Webster]

   Note: In the United States, the more prevalent expression has
         been "sales at auction," that is, by an increase of
         bids (Lat. auctione). This latter form is preferable.
         [1913 Webster]

   Dutch auction, the public offer of property at a price
      beyond its value, then gradually lowering the price, till
      some one accepts it as purchaser. --P. Cyc.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Auction \Auc"tion\, v. t.
   To sell by auction.
   [1913 Webster]

WordNet (r) 3.0 (2006):

auction
    n 1: a variety of bridge in which tricks made in excess of the
         contract are scored toward game; now generally superseded
         by contract bridge [syn: auction, auction bridge]
    2: the public sale of something to the highest bidder [syn:
       auction, auction sale, vendue]
    v 1: sell at an auction [syn: auction, auction off,
         auctioneer]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

AUCTION, commerce, contract. A public sale of property to the highest
bidder. Among the Romans this kind of sale, was made by a crier under a
spear (sub hasta) stuck in the ground.
     2. Auctions are generally held by express authority, and the person who
conducts them is licensed to do so under various regulations.
     3. The manner of conducting an auction is immaterial; whether it be by
public outcry or by any other manner. The essential part is the selection of
a purchaser from a number of bidders. In a case where a woman continued
silent during the whole time of the sale, but whenever anyone bid she gave
him a glass of brandy, and when the sale broke up, the person who received
the last glass of brandy was taken into a private room, and he was declared
to be the purchaser; this was adjudged to be an auction. 1 Dow. 115.
     4. The law requires fairness in auction sales, and when a puffer is
employed to raise the property offered for sale on bona fide bidders, or a
combination is entered into between two or more persons not to overbid each
other, the contract may in general be avoided. Vide Puffer, and 6 John. R.
194; 8 John. R. 444; 3 John. Cas. 29; Cowp. 395; 6 T. R. 642; Harr. Dig.
Sale, IV.; and the article Conditions Sale. Vide Harr. Dig. Sale, IV.; 13
Price, R. 76; M'Clel. R. 25; 6 East, R. 392; 5 B. & A. 257; S. C. 2 Stark.
R. 295; 1 Esp. R. 340; 5 Esp. R. 103 4 Taunt. R. 209; 1 H. Bl. R. 81; 2
Chit. R. 253; Cowp. R. 395; 1 Bouv. Inst., n. 976.