Cashew is ever-present in standard nut mixtures, which cobble Cashew together with a band of other hard, oily, unrelated seed that roast up nicely – Pecans, Brasil Nuts, Hazelnuts, and Peanuts. Of those, Cashew is not my favorite, but I know a lot of people who place it in higher esteem.
A Cook would look for Cashew among nuts and seed in a market, but this arrangement would drive a Systematist crazy. Cashews are produced by the tree Anacardium occidentale, a relative of Mango, Pistachio, and Brasilian Pepper, all of which might show up in differing sections of a good market. Of course, the plants in this family are part of a toxic klan, which includes Poison Ivy and Poison Oak. That chemistry might be present in other family members, as many people are allergic to components of both Cashew and Mango. Most particularly, the raw, one-seeded Cashew fruit is not considered edible; it must be shelled and roasted to eradicate allergenic properties.
Researching Cashew on the internet, you become aware that of all fruits, this one tests practically every understanding of our terminology. The 2017 Wikipedia entry, for example, discusses the “fruit” as compared to the “true fruit”, reflecting the fact that the green apostrophe at the stem tip is the “true fruit”, while people consider the marañon (the fleshy stem) as the fruit of this tree. Indeed, the appendicular nature of the Cashew fruit gives rise to the generic name, Anacardium, which suggests that in these plants, the seed forms outside the structure that appears to be a fruit (ana = away or outside; cardium = heart, i.e. fruit)
Do not get confused or bothered. In the Reader, the fruit is the mature, seed-containing ovary, not the juicy apple-like stem. You might read that this seed-containing fruit is a Drupe, but that is illogical because the “dispersal unit” is sepparate, an Accessory Fruit (the edible stem increases the chance a viable seed is dispersed further from the parent plant). For this reason, Dr. Spjut classifies Cashew as a Glans. I guess he would place it alongside Acorns, but that is misleading from my viewpoint. We have to find a different word for this.