"inch margin" refers to leaving a space of one inch (2.54 centimeters) empty around the edges of a page, such as in a document or a paper. It provides a visual buffer and helps make the text or content look balanced and organized. Full definition
Starting at one end, and allowing a 1 - inch margin on all sides, layer cabbage, carrots, apple, pomegranate seeds and salmon strips. (theglutenfreemaven.com)
Using a spoon, spread the pizza sauce onto the pizza crust, leaving a 1 / 2 - inch margin around the edges. (thespruce.com)