Integral means essential or necessary, so important to something that you can't imagine it working without that part. A goalkeeper is integral to a soccer team because the team can't function properly without someone defending the goal. Your brain is integral to your body, flour is integral to bread, and wheels are integral to a bicycle.

When something is integral, removing it would fundamentally change or break what remains. Think about your favorite book: certain characters might be integral to the story because without them, the whole plot would fall apart. In contrast, minor characters might be interesting but not integral since the story could survive without them.

When you call something integral, you're saying it's woven so deeply into the whole that separating it out would be like trying to remove eggs from a baked cake.

In mathematics, integral also refers to a concept in calculus about finding areas and accumulation, but you'll learn more about that when you're older.