Learner's definition of BOUNDARY
1 [count] : something (such as a river, a fence, or an imaginary line) that shows where an area ends and another area begins 2 [count] : a point or limit that indicates where two things become different 3 boundaries [plural] : unofficial rules about what should not be done : limits that define acceptable behavior
You need to set boundaries with your children.
Did he violate the boundaries of the doctor-patient relationship?
They're pushing the boundaries of [=doing things that are unusual in] traditional French cooking.
know no boundaries
1 : to be capable of affecting people everywhere