What is cornucopia and what is it's reference in Freemasonry?

The cornucopia, or horn of plenty, is an emblem of abundance derived from ancient Greek mythology 12. According to classical myth, the infant Zeus was nourished in Crete by the milk of the goat Amalthea 12. In gratitude, Zeus placed Amalthea among the stars as a constellation and bestowed one of her horns upon his nurses, assuring them that it would continuously yield whatever they desired 12.

The cornucopia serves as the official jewel of office worn by the Stewards of a lodge 12. Symbolically, it reminds the Stewards of their obligation to see that the tables are properly furnished during times of refreshment and that every brother present is suitably served 1.

Carl Claudy connects this symbol to astronomical geometry, noting that the goat Amalthea is associated with the constellation Capricorn 2. Because the Tropic of Capricorn marks the southern limit of the sun's path on the ecliptic, the jewel forms a symbolic link between the Stewards, the lights in the lodge, the place of darkness, and King Solomon's Temple 2.

In ceremonial contexts, such as the consecration of a lodge or the laying of a cornerstone, the cornucopia is used to carry corn, representing nourishmen, abundance, and the primary necessity of life alongside the vessels of wine and oil 1.