The dictionary defines a boundary as “something that indicates bounds or limits; a limiting, or bounding line.”
A boundary, in human terms, is where you end and I begin. To compare it to your yard, the boundary is where your yard ends and your neighbor’s yard begins. Your neighbor decides what type of flowers to grow in his or her yard; you do not tell him what to grow, and vice versa. Within relationships, it can sometimes be challenging to recognize and respect boundaries, however.
Boundaries basically mean that we respect another person’s rights. Any type of abuse would be considered a boundary violation. Being disrespectful in any way is a boundary violation. But boundary violations can be far more subtle than that.
As an example, if a parent disagrees with how an adult child is living her life, it may be tempting to try to tell the adult child what to do, but that is no longer appropriate. If the offspring is open to suggestions or advice, this is, of course, okay, but not to try to control. It can be painful to see a loved one making choices that you know will end up hurting them, and not be able to intervene. Knowing how to tread on that very fine line can be a real challenge.
When children grow into adults, the family goes through a transition, whereby the “children” become responsible for themselves, including their own mistakes. New boundaries are formed within the family, and family members must learn to relate to each other differently. Most families seem to go through this transition quite smoothly.
What is Enabling?
A lot of attention was drawn to the concept of boundaries through the Al-Anon movement, when the concept of “enabling” became part of our everyday 
language. Al-Anon is a 12-step program similar to Alcoholics Anonymous, and it is for the partners, friends and relatives of alcoholics. At first, people did not understand why the partners, relatives and friends of alcoholics would also need a 12-step program.
Helping someone is a positive thing. But, when one begins to take responsibility for someone else’s problems, and/or shield them from the consequences of their actions, then the other person has less pressure, less incentive, to change. Often, experiencing the consequences of their actions is the very motivation they need to change the behavior. An example would be a spouse who calls in for an alcoholic, and makes up a reason why the alcoholic spouse cannot go to work that day. As well-meaning as this can be, it makes it that much easier for the alcoholic to continue in the same course of action, because he does not need to deal with the situation, the consequences of his actions.
Of course, boundaries are not only important in the realm of alcohol abuse; this is merely being used as an example.
Alcoholics Anonymous: The Serenity Prayer
Alcoholics Anonymous, or A.A., is a wonderful organization that has helped thousands, probably millions of people. The Serenity Prayer is in some ways the cornerstone of the A.A. philosophy:
God grant me the serenity
To accept the things I cannot change,
The courage to change the things I can,
And the wisdom to know the difference.*
This prayer is many things, but it is partially a prayer about boundaries. To know the difference between the things I can and cannot change, is very important for all of us.
Usually the things we can change have to do with ourselves. The things we cannot change have to do with other people. We cannot change other people’s choices, decisions, problems, or the situations they choose. We do not have the power to change them. Even if we did, it would be a disservice to them, because it would be taking away the other person’s opportunity to learn and grow. In the long run, it would not really be helping them.
It is basically the difference between helping or offering advice, and trying to control.
Much of what psychotherapists do is to clarify boundaries in the client’s life. This is especially true in couples and family therapy, but it is also very important individual therapy. And it is a task well worth undertaking. Ultimately, people get along much better when they do respect each others’ boundaries.
It is important to know that, when it comes to personal choices about your life, you decide; and you do not even have to give an explanation why, if you do not want to.
Also, you can care about someone very much, and still not try to solve his or her problems. You can choose to give them a ride, but you do not have to; and if you choose not to, this does not mean that you care about him any less.
If you are chronically allowing someone else to violate your boundaries, or if you need help clarifying where the boundaries are in some of your relationships, that may be a very good time to seek help.
*From Alcoholics Anonymous The Big Book Fourth Edition (2001) New York, New York: Alcoholics Anonymous World Services, Inc.