The açaí palm, or aqai, ( , /ah-sah-EE/) is a member of the genus Euterpe, which contains eight species of palm trees that are native to Central and South America, from Belize southward to Brazil and Peru. These palms grow mainly in swamps and floodplains.

The genus is named after the muse Euterpe of Greek mythology. Euterpe are tall, slender palms growing to 15–30 meters, with pinnate leaves up to 3 meters long. Many of the palms that were once in the genus Euterpe have been reclassified into the genus Prestoea (Riffle, 2003). The species Euterpe oleracea is usually called Açaí Palm, after the European adaptation of the Tupian word ïwasa'i, 'that cries or expels water'.

Açaí palms are fast-growing, and are cultivated for both their fruits and for their superior hearts of palm. Global demand for the fruit has expanded rapidly in recent years, and açaí is now cultivated for that purpose primarily. The closely-related species Euterpe edulis (jucara) is now predominantly used for hearts of palm.

Stem

Heart of palm, the soft inner-growing tip of some palms (Euterpe edulis, , Bactris gasipaes), is often consumed in salads.Fact: date=July 2007

Fruit

The fruit, a small, round, black-purple drupe about 1 inch (25 mm) in diameter, similar in appearance and size to a grape but with less pulp, is produced in branched panicles of 700 to 900 fruits. Two crops of fruit are produced each year. The fruit has a single large seed about 0.25–0.40 inches (7–10 mm) in diameter. The exocarp of the ripe fruits is a deep purple color, or green, depending on the kind of açaí and its maturity. The mesocarp is pulpy and thin, with a consistent thickness of 1 mm or less. It surrounds the voluminous and hard endocarp, which contains a seed with a diminutive embryo and abundant endosperm.Fact: date=February 2007 The seed makes up about 80% of the fruit (Schauss, 2006c).

The berries are harvested as food. In a study of three traditional Caboclo populations in the Amazon region of Brazil, açaí palm was described as the most important plant species because the fruit makes up such a major component of diet (up to 42% of the total food intake by weight) and is economically valuable in the region (Murrieta et al., 1999).

The juice and pulp of açaí fruits (Euterpe oleracea) are used in various juice blends, smoothies, sodas, and other beverages. In northern Brazil, açaí is traditionally served in gourds called "cuias" with tapioca and, depending on the local preference, can be consumed either salty or sweet (sugar, rapadura, and honey are known to be used in the mix).Fact: date=February 2009 Açaí has become popular in southern Brazil where it is consumed cold as açaí na tigela ("açaí in the bowl"), mostly mixed with granola.Fact: date=February 2009 Açaí is also widely consumed in Brazil as an ice cream flavor or juice.Fact: date=February 2009 The juice has also been used in a flavored liqueur.Fact: date=February 2009