Nutmeg is the seed of the Myristica fragrans, a tropical, dioecious evergreen tree native to the Moluccas, or Spice Islands, of Indonesia. Nutmeg has a distinctive, pungent fragrance and a warm, slightly sweet taste; it is used to flavor many kinds of baked goods, confections, puddings, meats, sausages, sauces, vegetables, and beverages such as eggnog. Grated nutmeg has been used as a sachet; the Romans used it as incense. Around 1600 it became important as an expensive commercial spice of the Western world. It was the subject of Dutch plots to keep prices high, and of English and French counterplots to obtain fertile seeds for transplantation. Before whole nutmegs were sold, they were dipped in lime to prevent their sprouting. Connecticut is known as "The Nutmeg State" because of its importance in the nutmeg trade. History books sometimes include tales of slick Yankee peddlers selling whittled wooden "nutmegs" to unsuspecting housewives.

The tree is cultivated principally in the Moluccas and the West Indies, and elsewhere with varying success. The trees may reach a height of about 65 feet (20 metres). They yield fruit 8 years after sowing, reach their prime in 25 years, and bear fruit for 60 years or longer. The nutmeg fruit is a pendulous drupe, similar in appearance to an apricot. When fully mature, it splits in two parts, exposing a crimson-coloured aril (which is the mace), this surrounds a single shiny, brown seed, (which is the nutmeg). After collection, the aril-enveloped nutmegs are conveyed to curing areas where the mace is removed, flattened out, and dried. The nutmegs are dried gradually in the sun and turned twice daily over a period of six to eight weeks. During this time the nutmeg shrinks away from its hard seed coat until the kernels rattle in their shells when shaken. The shell is then broken with a wooden truncheon and the nutmegs are picked out. Dried nutmegs are grayish-brown ovals with furrowed surfaces. Large ones may be about 1 1/4 inches (30 millimetres) long and 3/4 inch in diameter.

Nutmeg and mace contain 7 to 14 percent essential oil, the principal components of which are pinene, camphene, and dipentene. Nutmeg on expression yields about 24 to 30 percent fixed oil called nutmeg butter, or oil of mace, the principal component of which is trimyristin. The oils are used as condiments and carminatives and to scent soaps and perfumes. An ointment of nutmeg butter has been used as a counter-irritant and in treatment of rheumatism.

The name nutmeg is also applied in different countries to other fruits or seeds: the Jamaica(or calabash), nutmeg derived from Monodora myristica; the Brazilian nutmeg from Cryptocarya moschata; the Peruvian nutmeg from Laurelia aromatica; the Madagascar (or clove), nutmeg from Ravensara aromatica; and the California (or stinking), nutmeg from Torreya californica.