If I point out that Drupal's taxonomy system – its amazing, flexible, powerful, wonderful taxonomy system – can be confusing, I'll only be about the eleven thousandth Drupalnik to do so. The thing is, though, the system is not that confusing; it's just the language that messes people up.

Categories, taxonomies, vocabularies, terms. One sees a couple other words, like classification, tossed into the mix at times too.

Taxonomy now!

If you want to get up to speed on what's called what, start here:

• http://drupal.org/node/937
• http://drupal.org/node/21857 (Yikes, this one adds yet another word, "topic", to the system, and suggests terms, categories, and "topics" are one and the same. And on top of that, it compares terms/categories/topics to folders on a hard drive – a terribly wrong analogy, IMO.)
• http://drupal.org/node/120624
• http://drupal.org/node/299 (see big bunch of links at bottom of this page)

It's hard to say what the single, short, definitive overview of taxonomy-related stuff is. You might have already derived your own; I think along these lines:

Terms are keywords – tags, if you prefer – for content. A vocabulary is a group of terms grouped by similarity (or by any other basis). Users mostly need only worry about setting and using terms and vocabularies.

Taxonomy is simply a name for how sites and users make use of terms; users won't have much need to invoke the word. Category is a word that's really superfluous to the discussion; users only need to know that the admin page for managing terms and vocabularies happens to be titled Categories.

Words like classification and topic need no special defined meanings, and can be used in their generic sense.

Does that overview work for you, reader, or am I off?

Taxonomy revised!

Here's how things could be cleaned up, methinks:

Call "terms" tags. Replace "vocabulary" with the instantly-clear label tag group. Chuck "taxonomy" in favor of tagging. And drop any special use of "category"; just give the Categories page the new title Tagging.

And as above, don't even think of dragging in any more words; leave poor classification, topic, etc. out of it!

So, that's my Drupal mystery: why the confusing words? It's hard for me to even write about the subject, as my fingers scream to use words like "term" and "vocabulary" in their generic sense, yet doing so will only cause confusion with those words' Drupal-specified meanings. (Excuse me while I make a side comment: Looking a little nervous after that last remark, "page" and "story" node types? You should be...)

Granted, I may be too critical here; Drupal's creators may have settled upon "term", "taxonomy" etc. before "tag" and "tagging" came into today's popular use. But if there's any chance of simplifying these terms (words, I mean; grrrr!) in the future, then how about it, Drupalites?