Nomenclature: Forum

This just a pet peeve, but I am seeing it more and more often...

This (the entity represented by the page on which you are reading these words) is not a "forum". This is a post. It contains one topic and (theoretically) one set of comments/replies. A post with a series of replies is a thread.

The entire "Site Feedback and Suggestions" group of postings...that is a forum. 

A thread contains a single discussion, a forum contains (and provides a platform for) multiple related discussions.

Calling threads "forums" just confuses things. Think of it this way...the word is from Latin, and refers to building(s)/an area where the Roman Senate discussed issues, etc. A forum here is like a virtual building, housing many smaller groups of people engaged in their own separate discussions (the posts/threads). An individual topic/discussion is not a forum.

I thought that each of our scrivenings was a post, and that they collectively formed a thread (this one entitled "Nomenclature: Forum"), and that the threads collectively formed a forum (this one named "General Chess Discussion"), and that the various forums together formed, well, forums (although one might prefer "fora," used less these days than "forums").

Well, that definition is a little more vague, from some perspectives there's one post, and the rest are replies (or in the case of blog article, one post with comments), and from another they are all posts.  From a developer perspective, and for database storage purposes, they would all probably be posts, tied to the same thread ID.

In any case, the term "forum" is right out :).

Forum is Latin for market.

Good to see that you have started a new thread about it. :-)

I commonly refer 'post' as a comment, as the #1 is just a comment on the public forum that you created.

The first comment is the "Original Post" (or possibly "Originating Post")--"OP." The replies are posts, too. The OP and its replies form a thread.

I thought that 'OP' would mean 'Original Poster', i.e, the creator of the forum(in this case, btickler).

OP is "original poster", yes.  I am the creator of this thread, but some chess.com admin is the creator of the forum this thread resides in :).

A forum is:  the marketplace or public place of an ancient Roman city forming the center of judicial and public business

Interestingly, your definition of forum is correct(i thought that was just a place to discuss something, but this concept can be more extended). From Web:

'In ancient Rome, it was known as a forum the public square where were treated the business of the people and where the trials took place. The forum used to be outside the city walls (incidentally, forum means "out") and constitute a point of contact between them and the outside.

At present, the concept maintains it's essence although with some adaptations and logical changes over time. A forum is a meeting or a meeting is held to discuss matters of interest in the presence of an audience, which can intervene in the discussion.

In this sense, a forum is a communication technique where by several people talk about a topic of common interest. The forum is collective and is directed by a moderator.

The experts participating in forums to exchange ideas and analyze problems in the area they represent, in general, before a group of assistants. A forum on new technologies, for example, may include the participation of entrepreneurs in the technology sector, engineers, analysts and programmers.

The notion forum acquired a remarkable dimension thanks to Internet forums, which are applications that allow you to express opinions and engage in discussions via the Web Forums Internet work from a message that is published by a user or a moderator and that gives rise to answers by other users. They are designed to allow follow the direction of the conversation from the original message to the latest responses.'

It was taken for Google Translate, as the original text isn't english, so there may be some grammar errors.