Back in early modern Brazil, and certainly before Europeans got there as well, cashew apples (the fruits) were fermented to make alcoholic beverages. People ate the fruits too, and the nuts, but the main function of the cashew tree in Brazil c.1500 seems to have been booze production.

It also seems that indigenous Tupi speakers used the cashew tree to measure the passing of time. The word "akaîuro'y" 'cold cashew' seems to have meant 'year' in Tupi, for instance. Here it is in the Tupi-Latin glossary at the end of Georg Marcgrave's "Historia Naturalis Brasiliae" (1648:276):