The Areca nut is the seed of the Areca palm (Areca catechu), which grows in much of the tropical Pacific, Asia, and parts of east Africa. It is commonly referred to as "betel nut" as it is often chewed wrapped in betel leaves.

The International Agency for Research on Cancer has concluded that chewing areca nut is carcinogenic to humans. It made this conclusion after reviewing the published scientific studies related to health effects of chewing areca nut.

The areca nut is not a true nut but rather a drupe. It is commercially available in dried, cured and fresh forms. While fresh, the husk is green and the nut inside is so soft that it can easily be cut with an average knife. In the ripe fruit the husk becomes yellow or orange and, as it dries, the fruit inside hardens to a wood-like consistency. At that stage the areca nut can only be sliced using a special scissor-like cutter (known as AdaKitta (अडकित्ता) in Marathi, Jati in Bengali, Sarota in Hindi, Paakkuvetti in Malayalam, Adake kattari in Kannada, Paakkuvetti in Tamil and Aḍakattera in Telugu, "sudi" in Gujarati, "Giraya" in Sinhala).

Nut, NUT, Nuts or NUTS may refer to: