"lawyer" and "attorney" are almost exactly the same. In America, you can call yourself a "lawyer" as soon as you graduate from law school, but you need to pass the bar exam and be licensed to practice law before you can call yourself an "attorney". A defendant's "counsel" is the specific lawyer or attorney who is working with that defendant on that case.

I'm English, so these words mean slightly different things to me. My knowledge of the American system comes from watching Perry Mason movies 30 years ago. I assume lawyer USA = lawyer UK. A generic term. I assume attorney = barrister (arguing cases in court). I assume counsel = barrister or solicitor (hired by the defendent, the solicitor for the initial paperwork, the barrister for court). We use the word attorney in a number of ways, but stick to solicitor, barrister or lawyer for the actual lawyers we deal with. And who voted Mr Broccoli down? It seems a reasoned and respectful viewpoint.

American attorney/lawyer/counsel here. All of these words mean the same, although as Chris points out the word "attorney" is a little more specific since it means someone who is licensed to appear in court. I would also say, though, that this distinction is a bit unclear and practically speaking you are not usually calling yourself a "lawyer" in the U.S. either unless you are licensed to practice. I respectfully disagree with Charles on the meaning of the word "counsel" - I think it is a synonym with attorney and lawyer. The reason that there are three words has to do with the history of English as a hybrid language, borrowing from Old English (Germanic), Norman French, and Latin. Since our system of common law started with the Norman invasion of England in 1066, judges and lawyers would often use three versions of the same word in legal situations. This tradition has continued to the present day, where we use the three words you mention here - lawyer (Old English), attorney (Norman French), and counsel (Latin). You see this in other legal documents too - e.g. "it is ordered, adjudged, and decreed..." This is a good illustration of why English is so complex - it is actually several languages that fused over time into one.

For me, attorney and lawyer are pretty much interchangeable, but attorney sounds more formal. I don't think you can call yourself a lawyer as long as you graduate from law school; I think you'd have to pass the bar first. Counsel can mean the same as lawyer and attorney but has different usages. First, when addressing a lawyer, you can call them "counselor." Kind of like calling a doctor "doctor." This is often used when you know someone is a lawyer but don't know their name. Lawyers often call each other "counselor" in court. Second, lawyers for companies are often called counsels, e.g. in-house counsel, general counsel. This is the usage in the US.

The words are often used interchangeably. A lawyer is a general term for an attorney or counselor, so you can use it in any situation. Attorney is usually used to describe someone representing a client in court or legal proceedings. Counselor is used to describe someone giving counsel, or legal advice.