I like to regularly remind people that the term "Centrist" is cooked-up DC jargon about how members of Congress vote and has nothing to do with the American political mainstream. If a member votes more often with the other party, they're "Centrist". This means that if a Democrat votes with the Republicans a lot, we can call that Democrat a "Centrist" rather than what you really are when you vote with crazy right-wing loonies, which is "a crazy right-wing loony".
Anyroad, R.J. Eskow has a useful dictionary for you if you're trying to parse the bizarre language you see on page and screen from the punditocracy, "The Progressive's Guide to Corporate Democrat Speak."