A cornucopia is a symbol of abundance and wealth. Traditionally, it is represented by a curved goat horn which overflows with grain and fruit. Modern cornucopias are often depicted as horn-shaped baskets filled with food, and this symbol is often associated with the harvest. This decorative device has a long and ancient history, with roots in Greek mythology.
According to legend, the god Zeus was nursed by a goat named Amalthea. In one version of the story, the young god accidentally broke off her horn, and felt guilty about it, so he returned it to her in enchanted form, declaring that the horn would be filled with whatever the holder desired. Other legends say that Amalthea broke her horn off herself, filling it with flowers and presenting it to Zeus. The Greeks believe that the Horn of Amalthea, as they called it, symbolized prosperity, since it could be endlessly filled with whatever the heart desired.
When the Romans were introduced to the concept, they adopted it as the cornu copiae, the "horn of plenty," using the device in their coins, statues, and works of art to represent abundance. Over time, the original Latin became corrupted into "cornucopia," and along the way, people began to associate the symbol of the overflowing horn with the harvest, and with plentiful amounts of something.
One interesting use of the cornucopia occurred in advertisements which were designed to entice settlers to North America. Depictions of cornucopias, rolling fields of grain, fruit trees, and other symbols of plenty were meant to appeal to people struggling with a hardscrabble existence. When settlers arrived, many discovered that the language and imagery on the posters was not exactly true to life.
In slang, people sometimes use the term "cornucopia" to describe a large volume of something, as in "there's a cornucopia of job opportunities there." This symbol also appears in many seasonal displays during the fall, especially at markets which stock food items. Harvest parades may also include a representation of the cornucopia, packed to the brim with a variety of foods. Many companies use the device in their logos, playing on associations with abundance among consumers.
It is not uncommon to see the cornucopia shape adopted for gift baskets during the holiday season, and some people use the device as a centerpiece at meals which commemorate the harvest. In America, for example, the cornucopia is strongly associated with Thanksgiving. Given the limited size of goat horns, the transition to horn-shaped baskets is perhaps not terribly surprising.