Which word should be used in the following? And why?
Please cut a circle/round from the green paper.
Which word should be used in the following? And why?
Please cut a circle/round from the green paper.
The shape is called a circle. We don't usually call the shape a round, so saying "Cut a round from the green paper" is confusing.
A circle is a shape that is round. There are other shapes that are also round, an oval, for example. Roundness can be attributed to many different shapes, but the state of being circular is attributed only to the circle shape.
I would revise your sentence to: "Please cut a circle out from the green paper."