A nut in botany is a simple dry fruit with one seed (rarely two)
in which the ovary wall becomes very hard (stony or woody) at
maturity, and where the seed remains attached or fused with the
ovary wall. So, hazelnuts, hickories, chestnuts and acorns are
true nuts. That leaves just about everything we call a nut as a
non-nut, typically a seed: - Almonds, pecans and walnuts are the
edible seeds of drupe fruits — the leathery “flesh” is removed
at harvest. - Brazil nut is the seed from a capsule. - Candlenut
(used for oil) is a seed. - Cashew nut is a seed. - Horse-
chestnut is an inedible capsule. - Macadamia nut is a creamy
white kernel (Macadamia integrifolia). - Malabar chestnut -
Peanut is a legume. - Pine nut is the seed of several species of
pine (coniferous trees). - Pistachio nut is the seed of a thin-
shelled drupe. Would you like some roasted drupe-fruit seeds?