# Glossary

## A

Account

- An account represents an identity within Claws Mail. As such only one email address is associated with each account. However, the number of accounts you can setup is unlimited.

Action (filtering/processing rules)

- An action is something that is performed on a message when it matches the rule conditions. A typical action is moving the message to a particular folder. See also gt_condition_rules.

Actions

- Actions are user-defined commands that can be applied to a message, or part of a message, using a special syntax. They are presented to the user in a customisable menu.

Address book

- Storage for names, mail addresses and custom user attributes. Also provides access to gt_ldap servers and gt_vcard files.

ASCII

- American Standard Code for Information Interchange. A standard gt_character_encoding using 7 bit. It's defined as an Internet standard in RFC 20.

Attachment

- Additional file(s) included with a mail message. Some attachments can be displayed by Claws Mail, others require external programs. gt_plugins can provide additional functions for attachments.

## C

Character encoding

- A map between written symbols, like letters and other symbols, and the numbers used to represent them inside the computer. The most well-known character encoding is probably gt_ascii, but it has been superseded by others, such as gt_utf8.

Compose

- Create new a message text or a reply to a received mail in the Compose window.

Condition (filtering/processing rules)

- The prerequisites that a mail message must fulfil in order for the rule's action to be executed. See also gt_action_rules.

## D

Digital signature (GPG)

- A piece of data obtained from merging a message and a cryptographic key which ensures message authorship, in a similar way that a hand-written signature does in a document. This piece of data is sent with the m essage so the recipient can verify its validity.

## E

Encryption (GPG)

- Scrambling a message with a cryptographic key so that only the recipient and ownwer of the key password can unscramble it for reading.

## F

Face

- A more modern implementation of the gt_xface, it's a coloured image (48x48 pixels) included in the message headers.

Filtering rule

- A gt_rule applied to incoming messages. Filtering rules can be also applied manually to the contents of any folder.

Folder

- A folder is the primary message container. Folders can be local or remote, but they are managed in a uniform way by Claws Mail.

Forward

- To send a copy of a received mail to another recipient, optionally adding your own message.

## H

Headers

- Machine readable lines which form the first part of a mail message. The purpose of headers varies; Typical headers are From and To which state the sender and recipient of the message, others are used by the mail system. Some headers are optional and are used to provide additional information, such as gt_xface or gt_face.

HTML

- Acronym for Hyper-Text Markup Language. It was the standard language to encode web pages in the beginning of the gt_www. Some mail clients use this language to encode the textual body of mails in order to craft special effects to text at the cost of multiplying the message size several times. HTML mail is also widely used by spammers to send gt_spam.

## I

IMAP4

- Internet Messaging Access Protocol (version 4). A protocol for accessing email on a remote server from a local client. All messages are stored in the remote server.

Immediate execution

- When the Execute immediately when moving or deleting messages option is used, operations performed on messages, (like deletions or movements), are performed immediately. If the option is turned off, all operations performed on messages by the user are only carried out when the Execute button is pressed.

ISP

- Internet Service Provider. A company which provides Internet access to its customers. In the dialup access age these were the big telephony companies, with the arrival of broadband access the number of companies and types of services offered has grown exponentially.

## L

LDAP

- Lightweight Directory Access Protocol. A protocol for accessing information directories such as organisations, individuals, phone numbers, and addresses.

LDIF

- LDAP Data Interchange Format. A text file format widely used for moving data between gt_ldap servers and/or other programs.

Local mbox file

- A local mailbox spool file in gt_mbox format.

Log window

- A special window which records protocol operations in detail that are performed by Claws Mail. It's a useful tool for debugging.

## M

Mailbox

- The root folder of the folder hierarchy.

Maildir

- A mailbox format in which all mail is kept in separate files. Maildir++ is an extension to the maildir format.

Mailing-List

- Electronic mailing-lists are a special usage of email that allows for widespread distribution of information to many Internet users. They often take the form of discussion lists, like the Claws Mail users' list, where a subscriber uses the mailing-list to send messages to all the other subscribers, who may answer in similar fashion.

Mark (message)

- An arbitrary indicator that can be set on a message by the user in order to draw attention to the message. Marks are shown in the Mark column of the Message List.

MBox

- A mailbox format in which all mail is concatenated and stored in a single file. The mbox format supported by Claws Mail is `mboxrd`.

Message

- A message is the basic piece of information handled by Claws Mail. A message is usually an email message, which is stored in gt_mh format on disk. Other kinds of messages (and storage formats) can be handled through gt_plugins.

MH

- A mailbox format in which all mail is kept in separate files. This is the default mailbox format used by Claws Mail.

MIME

- Multipurpose Internet Mail Extensions. Internet standards for representing binary data in gt_ascii text format, gt_headers encoding and gt_attachments.

## N

NNTP

- Network News Transfer Protocol. The protocol used to post, distribute, and retrieve gt_usenet messages, also called news articles or simply news for short.

Newsgroups

- A set of hierarchical partitions of gt_usenet messages on a gt_news_server. The gt_nntp protocol allows the user to subscribe to one or more newsgroups. New messages posted to the subscribed groups are automatically downloaded on connection.

News server

- Server which provides access to gt_usenet messages in gt_newsgroups through the gt_nntp protocol.

## P

PDF

- Portable Document Format. An open binary file format developed by Adobe Systems to allow interchanging of printable documents between different platforms. Inherits some features from gt_postscript but not being a language made it easier to process, especially on desktop computers.

PGP Inline

- Digital signing method which includes the signature data in the message body. Currently deprecated in favour of gt_pgp_mime.

PGP MIME

- Digital signing method which includes the signature data as a separate gt_mime gt_attachment.

Plugins

- External modules which can be loaded and used by Claws Mail to extend its functionality. Technically speaking these modules are shared libraries which can register one or several functions to be called by Claws Mail when something interesting is being done.

POP3

- Post Office Protocol (version 3). A protocol for retrieving email from a remote server. Messages can be automatically removed from server after downloading.

PostScript

- Page description language primarily used and understood by printing devices to generate its output. Was developed by Adobe Systems and is now a widely used standard in the printing industry. As it's a fully featured interpreted language it requires some processing power to deal with.

Privacy (GPG)

- Privacy provides methods for both signing and encrypting mail messages you send and also for verifying and decrypting signed and encrypted messages that you receive.

Processing rule

- A gt_rule or set of rules belonging to a folder which are executed on entering the folder.

## Q

Queue

- Temporary storage for messages which are waiting to be sent, either because they couldn't be sent due a network failure or because the user requested them to be sent later.

Quick Search

- A powerful way to search for messages using almost any criteria that you can think of.

Quotation

- When replying to a message the user will often include a quoted section of that message to provide the context. The quoted section is shown by the prepending of a common character, usually >.

## R

Recursive (Quick Search)

- A recursive gt_quick_search will also search in all subfolders of the selected folder.

Redirect

- To send a copy of a received mail in its original form to another recipient.

Reply

- Answer to a received message. As verb also the act of answering a message.

ROT-13

- Simple encryption method used since Romans age, which uses an alphabet rotated thirteen positions to encode each letter of the message. Used sometimes to hide funny messages on mails.

Rule

- Logical structure comprised of one or more conditions (see gt_condition_rules) and one or more associated actions (see gt_action_rules). Rules are used for filtering mail messages.

## S

SMTP

- Simple Mail Transfer Protocol. A protocol for sending email to servers.

SMTP server

- A server which receives mail messages from other hosts and/or sends mail messages to other hosts using the gt_smtp protocol.

Source (message)

- The full text of a message as it is transmitted over the network. This includes all headers, message body and encoded attachments if present.

Spam

- Junk mail, unsolicited commercial emails.

Spell checking

- Automatic verification of spelling while typing or after composition has finished.

SSL

- Secure Sockets Layer. A protocol used to encrypt and protect data sent over a network.

SSL certificate

- A certificate installed on a secure server that is used for identification.

STARTTLS

- STARTTLS (Start Transport Layer Security) is a command used to initiate a secure connection between two servers using gt_ssl.

Sticky (Quick Search)

- When the sticky option is set on gt_quick_search the search terms are not cleared when changing folders.

Synchronisation (folder)

- Making the contents of a local folder mirror those of an equivalent remote folder in the associated mail server.

## T

TCP

- Transmission Control Protocol. The main protocol used in the Internet. Allows media-independent reliable connections between two endpoints and is supported by all modern Operating Systems in use.

Themes

- Image sets for changing the appearance of buttons, folders and other graphical elements of Claws Mail.

Thread (messages)

- A set of messages loosely relating to each other.

Toolbars

- Sets of buttons arranged horizontally which provide access to all commonly used functions. Toolbars in Claws Mail can be customised.

## U

UIDL

- Unique IDentification Listing. A gt_pop3 command which allows single message handling by asigning a unique identifier for each message.

URL

- Uniform Resource Locator. A naming scheme for objects (usually files) in a multi-protocol networked environment like current Internet. For example, this is the one of the Claws Mail home page: `https://www.claws-mail.org`.

USENET

- User's Network. A bulletin board system of discussion groups, often called gt_newsgroups.

UTF-8

- 8-bit Unicode Transformation Format. A variable length character encoding capable of representing any universal character. An Internet standard defined in RFC 3629.

## V

vCard

- File format standard for Personal Data Interchange, it can hold information such as address, phone numbers, etc., much like the information usually found in a business card. They are commonly found attached to mail messages.

## W

Wrapping

- Restructuring of the message text based on a user-defined maximum number of characters per line. Wrapping ensures that paragraphs are justified, which means that they are aligned to the left and right margins.

WWW

- World Wide Web, the hyperlinked network of web pages across the Internet.

## X

X-Face

- Specially coded black and white image (48x48 pixels) included in the message headers. Capable mailers like Claws Mail and others can decode and show it alongside the message text. Although they are not unique, they can help to quickly identify the message sender. See also gt_face.