Define Your Terms

In a scene from "The Princess Bride" that keeps running through my head these days, Inigo Montoya turns to Vizzini and says, "You keep using that word. I do not think it means what you think it means." http://www.youtube.com/watch?v=G2y8Sx4B2Sk

It seems to me that much of communication suffers from the same issue: in a rush to reduce conflict, words have been watered down and their meanings changed to the point that one person says or writes a word intending one meaning while the hearer or reader interprets another. Then, communication doesn't happen.

So, it's time we review one of the first rules of good communications:

Before you say something important, define your terms.

It's easy to assume that your listener understands your words as you intend them, but we've discovered that more often than not, they don't. Often, it is very difficult to precisely define some terms, and it is those that it is best to address in your communications.

For example, I've lately been struck by the use of the word "love" in contexts as varied as Sunday sermons and teenage gigglefests. While I'm working on a series of articles about it that I'll post here in the future, right now I'll make the observation that many people would not agree on what it means. Is it a good feeling? A commitment? Physical intimacy? Or something else? How is it different from "like" or "devotion"?

Furthermore, it's not that any of these uses is wrong. It is simply that you, by using a word without clarifying what you mean by it, may deliver a very different message than you intend.

What words do you think are particularly troublesome in this way? How do you define your terms?