acorn
noun
"Acorn" is the fruit of an oak tree. It is a small, nut-like seed enclosed in a tough shell, often with a cup-like structure at the top. Acorns are typically found on oak trees and are a food source for various animals.
Example
1. I found an acorn lying on the ground.
2. The squirrels had been collecting acorns for the winter.
3. The acorns were crushed to make flour for the cake.