Wiktionary
n. 1 An early business card first produced at the beginning of the seventeenth century. 2 A trading card (such as a cigarette card).
Wikipedia
A trade card is a square card that is small, but bigger than the modern visiting card, and is exchanged in social circles, that a business distributes to clients and potential customers. Trade cards first became popular at the end of the 17th century in Paris, Lyon and London. They functioned as advertising and also as maps, directing the public to the merchants' stores (no formal street address numbering system existed at the time).
The trade card is an early example of the modern business card. Some businesses began to create increasingly sophisticated designs, especially with the development of color printing. A few companies specialized in producing stock cards, usually with an image on one side and space on the other side for the business to add its own information. As the designs became more attractive and colorful, collecting trade cards became a popular hobby in the late 19th century, since color images were not yet widely available.
In its original sense, the "trade" in trade card refers to its use by the proprietor of a business to announce his trade, or line of business. By moving into the realm of collecting, trade cards gave rise to the trading card, the meaning now shifting to the exchange or trade of cards by enthusiasts. Some cards, particularly those produced by tobacco companies featuring baseball players, later developed into collectibles and lost their function as a business advertisement.
Image:FloridaWaterTC1881.jpg|Lithographed trade card advertising Murray & Lanman Florida Water Cologne Image:Liebig-back.jpg|Back of a German Liebig Extract of Meat Trade Card from 1885 Image:Farinahaus1709-300dpi.jpg|Early 19th-century English-language trade card of John Maria Farina, cologne manufacturer, showing Farina Haus, Köln.