1.1 Glossary

This document uses the following terms:

ASCII: The American Standard Code for Information Interchange (ASCII) is an 8-bit character-encoding scheme based on the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that work with text. ASCII refers to a single 8-bit ASCII character or an array of 8-bit ASCII characters with the high bit of each character set to zero.

Augmented Backus-Naur Form (ABNF): A modified version of Backus-Naur Form (BNF), commonly used by Internet specifications. ABNF notation balances compactness and simplicity with reasonable representational power. ABNF differs from standard BNF in its definitions and uses of naming rules, repetition, alternatives, order-independence, and value ranges. For more information, see [RFC5234].

blind carbon copy (Bcc) recipient: An addressee on a Message object that is not visible to recipients of the Message object.

body: The contents of a body part or an entire message that contains several body parts, as described in [RFC2045].

body part: A part of an Internet message, as described in [RFC2045].

carbon copy (Cc) recipient: An address on a Message object that is visible to recipients of the Message object but is not necessarily expected to take any action.

character set: A mapping between the characters of a written language and the values that are used to represent those characters to a computer.

Coordinated Universal Time (UTC): A high-precision atomic time standard that approximately tracks Universal Time (UT). It is the basis for legal, civil time all over the Earth. Time zones around the world are expressed as positive and negative offsets from UTC. In this role, it is also referred to as Zulu time (Z) and Greenwich Mean Time (GMT). In these specifications, all references to UTC refer to the time at UTC-0 (or GMT).

distinguished name (DN): A name that uniquely identifies an object by using the relative distinguished name (RDN) for the object, and the names of container objects and domains that contain the object. The distinguished name (DN) identifies the object and its location in a tree.

distribution list: A collection of users, computers, contacts, or other groups that is used only for email distribution, and addressed as a single recipient.

email address: A string that identifies a user and enables the user to receive Internet messages.

encoding: A process that specifies a Content-Transfer-Encoding for transforming character data from one form to another.

header: A name-value pair that supplies structured data in an Internet email message or MIME entity.

mailbox: A message store that contains email, calendar items, and other Message objects for a single recipient.

MIME attachment: A body part that is in a MIME message, for example, an email message or a file that is attached to an email message.

MIME content-type: A content type that is as described in [RFC2045], [RFC2046], and [RFC2047].

MIME message: A message that is as described in [RFC2045], [RFC2046], and [RFC2047].

Multipurpose Internet Mail Extensions (MIME): A set of extensions that redefines and expands support for various types of content in email messages, as described in [RFC2045], [RFC2046], and [RFC2047].

recipient: An entity that can receive email messages. 

recipient forwarding: A feature that enables a message to be redirected to a different email address, which is referred to as the "forwarded address," from the address to which it is sent originally. Depending on the implementation, a message can be redirected to the forwarded address without sending a copy to the original email address, or the original email address can additionally receive a copy of the message.

Simple Mail Transfer Protocol (SMTP): A member of the TCP/IP suite of protocols that is used to transport Internet messages, as described in [RFC5321].

To recipient: See primary recipient.

MAY, SHOULD, MUST, SHOULD NOT, MUST NOT: These terms (in all caps) are used as defined in [RFC2119]. All statements of optional behavior use either MAY, SHOULD, or SHOULD NOT.