The phrase "staple part" refers to something that is essential or commonly used in a certain context or situation. It is like a fundamental or necessary component that is relied upon consistently. Full definition
What clothing pieces of these wardrobe staples part 2 do you own? (thefashionfolks.com)
With increasing number of food allergies and intolerance based on grain and grain products, it becomes crucial for us to reconsider the way grains are looked upon as staple part of diet. (paleodietfoodlist.net)
If you can tolerate these foods (don't have food sensitivities to them or problems with oxalates or high histamines) than consume as staple parts of your diet. (drjockers.com)