Trade dress protects a product's image. Acting as a source identifier, trade dress is essentially an unregistered product trademark under Section 43(a) of the Lanham Act 15 U.S.C. 1125(a). In some instances the trade dress is reflected in the combination of packaging and labels and in other instances, it is the product configuration that constitutes the trade dress. The total image of a product may include features such as size, shape, color or color combinations, texture and graphics. The shape of a bottle containing shampoo can be trade dress. Similarly, the shape or ornamental features of a chair, it's configuration, can constitute trade dress.

Trade dress protection and infringement can be one of the thorniest issues to tackle. Questions of protection or infringement will very often raise patent issues. In the case of the chair, is the chair design acting as trademark (trade dress) or is it acting less as a trademark and more properly subject to design patent protection? If the chair configuration is functional, is it pre-empted by patent law, which is intended to protect the functional aspects of an article of manufacture? If it's trade dress, it can be protected indefinitely but, if its only subject to patent protection, a monopoly is granted only for a limited time. If the trade dress is registered on the Principal Register of the U.S. Trademark Office, it will be presumed that it is non-functional. Absent registration, however, it becomes incumbent upon the person asserting trade dress in an infringement action to prove that the matter sought to be protected is non-functional, 15 U.S.C. § 1125(a)(3). A product feature is functional, and cannot serve as a trademark, if it is essential to the use or purpose of the article or if it affects the cost or quality of the article. The U.S. Supreme Court has observed that a functional feature is one "the exclusive use of [which] would put competitors at a significant non-reputation-related disadvantage. This is consistent with the separation between patent law, protecting the utilitarian features of a patented article, and those of trademark law, concerned primarily with identifying the products source.

Aside from the functionality issue, holders of unregistered trade dress also bear the burden of proving the trade dress is "distinctive". Being "distinctive" means the trade dress is serving to distinguish the product originator from its competitors. In other words, it's a trademark. A trademark or trade dress can be "inherently distinctive" or have "acquired distinctiveness". distinctive are marks whose intrinsic nature naturally serves to identify their particular source. Marks acquire distinctiveness through "secondary meaning". Through time and sales promotion efforts, the public has come to identify the mark or trade dress with a single source. Product designs, or colors, are not inherently distinctive. It is presumed that a product's design or color choice is selected for utility or aesthetic purposes rather than to identify the manufacturer. After some effort, however, even these trade dress elements may acquire distinctiveness. Product packaging, in contract, can be inherently distinctive, even absent registration. And what if the line drawn between product configuration and product packaging is blurred; the item incorporating features of both? In that instance, the burden of sustaining trade dress protection by proving "acquired distinctiveness" will fall to its holder.