mail user agent
<messaging> (MUA) The program that allows the user to compose
and read {electronic mail} messages. The MUA provides the
interface between the user and the {Message Transfer Agent}.
Outgoing mail is eventually handed over to an MTA for delivery
while the incoming messages are picked up from where the MTA
left it (although MUA's running on single-user machines may
pick up mail using {POP}).
Popular MUAs for {Unix} include {elm}, {mush}, {pine}, and
{RMAIL}.
FAQ
(http://cis.ohio-state.edu/hypertext/faq/usenet/mail/setup/unix/part2/faq-doc-3.html).
(1996-03-21)