be·tel / ˈbētl/ • n. 1. the leaf of an Asian evergreen climbing plant, used in the East as a mild stimulant. Parings of areca nut, lime, and cinnamon are wrapped in the leaf, which is then chewed, causing the saliva to turn red and, with prolonged use, the teeth to go black. 2. the plant (Piper betle) of the pepper family from which these leaves are taken.

betel Leaf of the creeper Piper betel, which is chewed in some parts of the world for its stimulating effect, due to the presence of the alkaloids arecoline and guvacoline. The leaves are chewed with the nuts of the areca palm (called pinang in Malaysia), Arecha catechu, which is therefore often called the betel palm, and the nut is called betel nut. The Indian delicacy pan is based on betel leaf and areca nut, together with aromatic spices and herbs.

betel leaf of the plant Piper betle. chewed in the East with areca nut. XIV. — Pg., of Dravidian orig. (Malayalam veṟṟila, etc.).
Hence betel-nut areca nut XVII.