The phrase "major part" refers to a large or significant portion, typically more than half. It can be used in various contexts such as describing a majority of something, an overwhelming number, or simply a substantial amount.
Dogs and cats have become major parts of millions of American families, and when summer brings hot weather and vacation travel, pets need special attention. (articles.orlandosentinel.com)
I constantly had to replace major parts in the car such as the radiator, spark plugs, fuel filter, etc.. (autolist.com)
This is as major part of the relationship for the young men involved in a sugar momma relationship. (seekingcougar.com)