Auction
An offering of art and collectibles where the buyer must bid against other potential buyers, as opposed buying the item retail

Auction catalog
A catalog that lists all of the items being offered for sale at a specific auction. Auction catalogs usually contain a description of the items being offered, often including statements about the provenance, literature, rarity, and importance of the items. Most catalogs include photos and a high and low estimate.

Authentication
Verifying the originality or genuineness of an item. The process differs for different categories of collecting.

Condition
The state of preservation of an item. Condition is a big component of value in most collectibles fields and can often double if not triple the price. The better the condition, the more desirable an item is, and thus, the more valuable it is.

Fair Market Value
The price that an interested but not desperate buyer would be willing to pay and an interested but not desperate seller would be willing to accept on the open market assuming a reasonable period of time for an agreement to arise. Usually used for auction pricing.

Letter of Authenticity (LOA)
A letter stating that a certain piece is authentic. This should come from an expert or reliable source. Do not except just anyone's LOA.

Literature
A term used to show if the item has been published in a book, catalog raisonne, museum exhibition or newsletter, etc. This can also add to the importance of the piece.

Limited edition
A term often used by publishers or manufactures to indicate scarcity. A limited edition means just that - production of the item in question will be limited to a certain number. However, that number may be large or small and may not affect the value.

Provenance
The history of ownership of a particular item. It allows the buyer to secure additional insight as to the origin of the item.

Rarity
The supply side of the supply/demand equation. The fewer examples available of an item, the more rare the item, and, the harder it is to find that piece.

Replacement Value
Usually used for insurance, the value of an asset as determined by the estimated cost of replacing it at a given time.

Professional appraisals
Usually of personal property can be used for many purposes such as insurance, estate tax, damage claims, donation, sale, dissolution of marriage and equitable distribution.