A betel nut is a nut that comes from a plant called Areca. It is sometimes used to make medicine. Betel nut is chewed alone or in the form of quids, a mixture of tobacco, powdered or sliced betel nut, and other ingredients. A betel nut is a nut that comes from a plant called Areca. It is sometimes used to make medicine. Betel nut is chewed alone or in the form of quids, a mixture of tobacco, powdered or sliced betel nut, and other ingredients.