Judging, literally, is to judge something as an isosceles triangle, that is to say, if you see a sentence that says "XXX is an isosceles triangle" in the future, that is the judgment of an isosceles triangle.

Nature, that is, the characteristics of isosceles triangle. So you will see that the description is "isosceles triangle …", which is nature.

There are many ways to judge whether a figure is an isosceles triangle, but one and only one is its definition: a triangle with two equal sides is an isosceles triangle, so you only need to remember the unique definition in future judgment.