Confused by all the abbreviations used in collectible art auctions? Here's a quick guide to some of the most popular:

Art Squared - This refers to 4x4 artwork made by members of the Art Squared group on Yahoo.

SFA - This stands for Small Format Art, and may also indicate that the work has been created by a member of the SFA group on eBay.

ZNE - Work created by members of the art group Varizione.

EBSQ - Work tagged with these letters indicates the artist is a member of EBSQ, a group for self-representing artists.

WWAO - Worldwide Women Artists. An international collective of women artists showing and selling their work online

OOAK - Short for one of a kind. Many artists use this to describe a unique piece of work.

NR - No reserve. This indicates that there is no pre-set price that must be met in order for the work to sell. The highest bidder in a NR auction will win.

ACEO - This stands for Artist Cards, Editions and Originals. These folks are bascially selling artist trading cards, which are meant to be traded between artists and not sold. Work is the standard 2.5 x 3.5 inch size of artist trading cards.

ATC - Artist Trading Card. A form of art created to be traded between artists, and not sold. ATCs have two basic rules: they are always 2.5 x 3.5 inches, and they must be able to slide into a trading card sleeve.