Distribution list is a term sometimes used for a function of email clients where list of email addresses is used to email everyone on the list at once. This can be referred to as an electronic mailshot. It differs from a mailing list

Mailing list

A mailing list is a collection of names and addresses used by an individual or an organization to send material to multiple recipients. The term is often extended to include the people subscribed to such a list, so the group of subscribers is referred to as "the mailing list", or simply "the...

, electronic mailing list

Electronic mailing list

An electronic mailing list is a special usage of email that allows for widespread distribution of information to many Internet users. It is similar to a traditional mailing list — a list of names and addresses — as might be kept by an organization for sending publications to...

 or the email option found in an Internet forum

Internet forum

An Internet forum, or message board, is an online discussion site where people can hold conversations in the form of posted messages. They differ from chat rooms in that messages are at least temporarily archived...

as it is usually for one way traffic and not for coordinating a discussion. In effect, only members of a distribution list can send mails to the list.