List of things that start with the letter O.
Orange orangutans avildy ogle an orchard of oleanders in Oregon.
Oaks are a group of trees and shrubs from the Northern hemisphere. There are both deciduous and evergreen oaks. Most people are familiar with the common oak trees that grow acorns.
Oak wood is used for making furniture, and was once used for making houses. It is still used for making wine barrels.