Is an acorn the same as a hazel nut?

A macadamia nut is not the same as a hazel nut.

Hazel nuts are sometimes called filberts or cobs.

A macadamia nut is a very hard-shelled nut which is very tasty either raw or roasted. It is native to the eastern coast of Australia, where it is popular, either eaten alone or in cooking. The macadamia nut is also known as the "Queensland nut" or, in some area, "bauple nut" (pronounced "bopple").