This is what you are supposed to use this thing for---reading news. News is generally fetched from a nearby NNTP server, and is generally publicly available to everybody. If you post news, the entire world is likely to read just what you have written, and they'll all snigger mischievously. Behind your back.

Everything that's delivered to you personally is mail. Some news/mail readers (like Gnus) blur the distinction between mail and news, but there is a difference. Mail is private. News is public. Mailing is not posting, and replying is not following up.

Send a mail to the person who has written what you are reading.

Post an article to the current newsgroup responding to the article you are reading.

Gnus gets fed articles from a number of backends, both news and mail backends. Gnus does not handle the underlying media, so to speak---this is all done by the backends.

Gnus will always use one method (and backend) as the native, or default, way of getting news.

You can also have any number of foreign groups active at the same time. These are groups that use non-native non-secondary backends for getting news.

Secondary backends are somewhere half-way between being native and being foreign, but they mostly act like they are native.

A message that has been posted as news.

A message that has been mailed.

A mail message or news article

The top part of a message, where administrative information (etc.) is put.

The rest of an article. Everything not in the head is in the body.

A line from the head of an article.

A collection of such lines, or a collection of heads. Or even a collection of NOV lines.

When Gnus enters a group, it asks the backend for the headers of all unread articles in the group. Most servers support the News OverView format, which is more compact and much faster to read and parse than the normal HEAD format.

Each group is subscribed at some level or other (1-9). The ones that have a lower level are ``more'' subscribed than the groups with a higher level. In fact, groups on levels 1-5 are considered subscribed; 6-7 are unsubscribed; 8 are zombies; and 9 are killed. Commands for listing groups and scanning for new articles will all use the numeric prefix as working level.

No information on killed groups is stored or updated, which makes killed groups much easier to handle than subscribed groups.

Just like killed groups, only slightly less dead.

The news server has to keep track of what articles it carries, and what groups exist. All this information in stored in the active file, which is rather large, as you might surmise.

A group that exists in the `.newsrc' file, but isn't known to the server (i.e., it isn't in the active file), is a bogus group. This means that the group probably doesn't exist (any more).

The act of asking the server for info on a group and computing the number of unread articles is called activating the group. Un-activated groups are listed with `*' in the group buffer.

A machine one can connect to and get news (or mail) from.

A structure that specifies the backend, the server and the virtual server settings.

A named select method. Since a select method defines all there is to know about connecting to a (physical) server, taking the thing as a whole is a virtual server.

Taking a buffer and running it through a filter of some sort. The result will (more often than not) be cleaner and more pleasing than the original.

Most groups store data on what articles you have read. Ephemeral groups are groups that will have no data stored---when you exit the group, it'll disappear into the aether.

This is the opposite of ephemeral groups. All groups listed in the group buffer are solid groups.

These are article placeholders shown in the summary buffer when gnus-build-sparse-threads has been switched on.

To put responses to articles directly after the articles they respond to---in a hierarchical fashion.

The first article in a thread is the root. It is the ancestor of all articles in the thread.

An article that has responses.

An article that responds to a different article---its parent.

A collection of messages in one file. The most common digest format is specified by RFC1153.