Etymology
Portuguese word, from Tupi

History

The saga of the cashew began in 1558, but the first written mention dates to 1578. The Portuguese brought the cashew tree from its native Brazil to India, Africa and Asia. For 400 years, the cashew was grown for its flavor, high vitamin C content and medicinal properties.

In Brazil, however, the cashew had been grown long before the arrival of Europeans. For thousands of years, the indigenous tribes used the nuts and juice to treat fever and freshen the breath. The Tikuna tribe, northwest of the Amazon, considered the juice the best remedy for influenza and for treating warts.

In Brazil, it is called the multi-purpose tree. The roots are used by the inhabitants of Guinea Bissau to strengthen their fishing nets. 

The multi-purpose tree
The wood of the cashew has the singular property of being water-resistant. In Africa, it is used to build small boats and ferries. 

However, it also has a dark side and was long referred to as the American poison, in the same way as sumac, because of the caustic sap found in the shells. This resinous substance is used in resins (naturally), but also in making adhesives, varnish and natural insecticides and is even used in aeronautics, making brakes, etc. In the Philippines it is used to waterproof roofs. It played an important role in World War II.