Cashews are actually seeds, not true nuts. True nuts are seeds contained within a hard shell that doesn't open naturally. Cashew nuts are considered nuts in the culinary sense, and they are often roasted and consumed as a snack or added to recipes in ethnic Indian cuisine.
Cashews grow out of fruits called cashew apples. These edible but delicate fruits have a sweet and astringent taste that lends itself well to making jams, jellies and liquor. Cashews are also used in cooking, or eaten fresh.
Cashew shells contain irritating compounds, such as anacardic acid, that neutralizes once the nuts are roasted. These compounds are used in the production of drugs, fuels, resins and lubricants.