From The Collaborative International Dictionary of English v.0.48 [gcide]:
Forum \Fo"rum\, n.; pl. E. Forums, L. Fora. [L.; akin to
foris, foras, out of doors. See Foreign.]
1. A market place or public place in Rome, where causes were
judicially tried, and orations delivered to the people.
[1913 Webster]
2. A tribunal; a court; an assembly empowered to hear and
decide causes.
[1913 Webster]
He [Lord Camden] was . . . more eminent in the
senate than in the forum. --Brougham.
[1913 Webster]
From The Free On-line Dictionary of Computing (8 July 2008) [foldoc]:
forum
fora
topic group
<messaging> (Plural "fora" or "forums") Any discussion group
accessible through a dial-in BBS (e.g. GEnie, CI$), a
mailing list, or a Usenet newsgroup (see {network,
the}). A forum functions much like a bulletin board; users
submit postings for all to read and discussion ensues.
Contrast real-time chat or point-to-point personal e-mail.
[Jargon File]
(1998-01-18)
From Jargon File (4.4.4, 14 Aug 2003) [jargon]:
fora
pl.n.
Plural of forum.