ellipse
yes. many teachers believe it is an oval, but the letter O is a perfect circle because if it was an oval, it would be confused with a zero.
You can evolve happiny with an oval stone after its friendship is high
The Pokemon that can use oval stone in Pokemon platinum is Happiny. It is the pre evolve form of chansey. Mostly every chansy you catch have a oval stone.
The Oval Stone evolves a Happiny into Chansey however it needs to be leveling up while it's holding the Oval Stone during the day time.
The shape of a flattened circle is called an ellipse. The shape is similar to an oval and some may mistakenly call it an oval.
A line.
technically it's an ellipse, but if you called it an oval you wouldn't be too far wrong.
ellipse
I think you mean an ellipse.
Head
The President's office is called the oval office.
a circle that has been flattened a little is an
Oval. It is called the Oval Office.
oval lines
If by "flattened" you mean "like someone took a sphere and sat on it", that would be an oblate spheroid.
It is called an oval - which is not the same as an ellipse.