Here's what I found:

1- The power to determine, adjudicate, or otherwise settle issues or disputes; jurisdiction; the right to control, command, or determine.

2- A power or right delegated or given; authorization: Who has the authority to grant permission?

3- An accepted source of information, advice, etc.

4- An expert on a subject: He is an authority on baseball.

5- Persuasive force; conviction: She spoke with authority.

6- Right to respect or acceptance of one's word, command, thought, etc.; commanding influence: the authority of a parent; the authority of a great writer.

7- Mastery in execution or performance, as of a work of art or literature or a piece of music.

These are actually only a sample, there are more... No wonder people are confused but the point here is that I wouldn't say that any of these are particularly negative. Nevertheless, I get the impression that people tend to see "authority" as a rather negative notion, a sort of dictatorial idea of the way things should be done. I really think that's a misconception.

Let me focus a little on #6. We are talking about right and acceptance, of thoughts and influences. The authority of a parent or a teacher is guidance, direction for kids. And let's see the other definitions too: as parents, you are the expert on the subject of life and growing up and being a teenager, you are the accepted source of information, you are the person who settles issues and disputes and you have mastery of your role as a mum or dad. There is no doubt that you ARE the authority and that is the best thing that can happen to your kids.

You don't have to be a dictator. But you have to make sure that you are in charge and that your kids know it. Why? Because of all of the above, you simply know better. Without using "because I said so" all the time, you can calmly explain your decisions to your kids, at any age, so that they understand why certain things have to be a certain way. Of course you can ask for their feedback and suggestions, but don't negotiate too much. Be clear and keep things simple to keep your authority.