Words that start with O

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.

An oar, sometimes called a paddle, is a long, thin pole with a wide, flat part at one or both ends. It is used to make a small boat like a canoe move forward, and to help in steering it.

Oats are a cereal crop grown mainly for turning into rolled oats and oatmeal for making porridge. It is also used as animal feed, particularly for horses.

You are obese if you are very fat or overweight. Obese people often have health problems because of their size.

Oboes are a double reed musical instrument in the woodwind family. Oboes have a very clear sound, and can be heard over other instruments. They have a conical hole through their centre, unlike the flute which has a cylindrical one.

An observatory is a building that is made as a place to watch the stars and planets. Observatories are dome-shaped and are usually built on top of high mountains so there is less air between them and space.

An obstacle is something that gets in your way when you are trying to do something or go somewhere.

An obtuse angle is one that is larger than 90 degrees. A 90 degree angle is a "normal" corner, like you find inside most houses and the corners of a piece of paper. An angle smaller than 90 degrees is called acute.

Oceania is a part of the world made up of many islands and countries in the Pacific Ocean. It includes places like Australia, New Zealand, and many Pacific island nations.

New Zealand did not quite fit in the picture, but you can click through to the link below to see the whole series of images from NASA.

Ochre is a natural earth pigment made from clay and minerals containing iron. It is usually yellow, orange, brown, or red. Ochre is found as soft earth or rock and can be ground into a powder. Ochre is also used as a name for a yellowish brown color.

People have used ochre for thousands of years to make paint. Early humans used it in cave paintings. Artists can mix ochre powder with water, oil, or other liquids to make paint. The word comes from an ancient Greek word meaning "pale yellow."