cashew nut (the edible nut of the cashew tree)
It is a fruit called a cashew apple- very sweet and good. The nut grows attached to the fruit. I believe the nut/seed is poisonous when raw.
16-18 cashews depending on their size
No. It is a type of nut.
Cashew is not a nut or a legume. It is a seed that stems from the bottom of the cashew apple which grows on trees. The cashew is a seed.