Every so often, someone on Less Wrong uses a word wrong.

What does it mean to use a word wrong? Can't we use language however we want, as long as we manage to successfully communicate? Well, yes, we can, but we shouldn't. Jargon terms, in particular, are used by professionals in a certain field in order to communicate concepts that are applicable chiefly in that field. They often have very precise definitions—"incunable", for example, means "book printed in Europe before the year 1501", and "sweet crude oil" means "petroleum with a sulfur content less than 0.42%".

The thing about precisely-defined terms like these is that if you use one of them in a way that's at odds with its official definition, you can cause people to have more misunderstandings later on. I admit I can't think of a great example, but "obsessive–compulsive disorder" seems like a decent one: people often say "I'm so OCD" to mean that messy things annoy them, which seems like it could lead people to misunderstand when people actually have obsessive–compulsive disorder.

There are just two words I don't really like LW's usage of:

• "Signaling". I'm not actually sure exactly what "signaling" means—which is arguably reason enough for us not to use it. I get the impression that it's usually used to mean exactly the same thing as "indicating". If that's the case, we should stop using it (or else only use it when everyone knows exactly what we mean by), and just say "indicating" instead. Or perhaps we don't use "signaling" to mean exactly the same thing as "indicating", but if that's the case, I don't know what the difference is, and I don't know whether or not it matches the "real" meaning of the word.
• "Affect" (the noun). Wiktionary defines it as "a subjective feeling experienced in response to a thought or other stimulus; mood, emotion, especially as demonstrated in external physical signs". LW seems to use it as an exact synonym of "emotion".