Photo of walnuts.

List of nuts and seeds

Most of these you can eat, some are just interesting to learn about.

is for
Almond

Photo of almonds
Photo by Harsha K R
Attribution-Sharealike
Scientific name: prunus dulcis

The almond is the seed inside the fruit of the almond tree. Almond trees grow up to 10 metres tall. They are related to plums, cherries and apricots. Most people think of almonds as a nut, not the seed of a fruit.
Almonds can be eaten raw or roasted and salted, or used in cooking cakes and puddings.

Scientific name: bertholletia excelsa

Brazil nuts are the seeds of a tree from South America. The Brazil nut tree is a very large tree, and the nuts only grow when the tree is in an undisturbed forest. The insects that pollinate the Brazil nut flowers are only found near a particular kind of orchid.
The Brazil nuts themselves grow inside a large fruit the size of a coconut, with the nuts in shells like in the picture arranged like the segments of an orange.

is for
Cashew

Scientific name: anacardium occidentale

The cashew, or caju, is a small tree native to Brazil. Cashew nuts are the seeds of the cashew apple, and are found in the grey bump at the end of the fruit in the picture. The cashew apple itself is sweet, soft and juicy.
Cashews are usually sold roasted and salted and eaten as a snack.

is for
Chestnut

Photo of a chestnut in its shell
Photo by Pizzodisevo
Attribution-Sharealike
Scientific name: castanea sativa

A chestnut is the seed of a tree related to the oak tree, which grows in the northern hemisphere. It grows its seeds in a spikey shell.
Chestnuts can be eaten raw but they do not taste very good this way. They are most often roasted before you eat them, but they can also be eaten candied, boiled, steamed, grilled or used as a stuffing.

is for
Hazelnut

Scientific name: corylus avellana

Hazelnuts are the nut of the hazel tree, and are very commonly used as an ingredient in chocolates, cakes and cookies (biscuits). Most hazelnuts are grown in Turkey. Hazelnuts can also be eaten raw or roasted.

Scientific name: genus: macadamia

Macadamias are medium sized evergreen trees native to the northern parts of Australia. Not all macadamia trees have edible seeds, only macadamia integrifolia and macadamia tetraphylla are cultivated. The others have toxic seeds. The macadamias that people eat are toxic to dogs, and can temporarily paralyze them.

is for
Peanut

Scientific name: arachis hypogea

The peanut is not a true not and, in fact, related to the pea - they are both legumes. Peanuts develop in a pod, like peas, with 1-4 peanuts in each pod. The pods force themselves underground to mature. Peanuts are usually sold in shops removed from their shell, roasted and salted. Peanuts are also frequently ground into a fine paste called peanut butter which is good to eat on sandwiches with jam or jelly.
Some people get a violent allergic reaction to eating peanuts, called anaphylactic shock, which can kill them. As this allergy is more common in children and more children each year are being found to have it, peanuts are often banned in schools.
The peanuts in the picture are unopened, still in their shells.

is for
Pecan

Scientific name: carya illinoinensis

Pecans are the fruit of a kind of hickory tree, native to North America and Mexico. They have a rich taste, and are most commonly used in sweets and desserts.

is for
Pine nut

Photo of pine nuts
Photo by Miles Goodhew
Attribution-Sharealike
Scientific name: pinus pinea

Pine nuts are the seeds of pine trees, most notably the stone pine. All pine tree seeds are edible, but only some varieties are big enough to be worth harvesting. Most pine nuts you buy in shops come from stone pines.
Pine nuts are a major ingredient of pesto.

Photo of pistachio nuts
Photo by Casey Fleser
Attribution-Sharealike
Scientific name: pistacia vera kerman

Pistachios are the seeds of a medium sized tree native to Iran, Syria, Greece, Turkey, Pakistan, and Afghanistan. They are also called the green nut. The trees are slow to mature and are most productive at 20 years old. The trees grow best in desert areas, and tolerate very salty soil.
Pistachio shells pop open when they are ripe. They are most often sold roasted and salted and just eaten plain, but they can also be used in desserts and some other types of food.

And also ...

Kola.