Proportion “a part, share, or number considered in comparative relation to a whole” (google)

When a Composition is in the same size or bigger than a another item.

Rule of Thirds “The basic principle behind the rule of thirds is to imagine breaking an image down into thirds (both horizontally and vertically) so that you have 9 parts”

(https://digital-photography-school.com/rule-of-thirds/)

A guideline cut into thirds mostly used for photography and film.

https://i0.wp.com/digital-photography-school.com/wp-content/uploads/2016/07/the-rule-of-thirds-1-1.jpg?resize=250%2C184&ssl=1

Golden Rule “There’s a common mathematical ratio found in nature that can be used to create pleasing, natural looking compositions in your design work.” (http://www.creativebloq.com/design/designers-guide-golden-ratio-12121546)

A Ratio used to calculate a design.