Forums is good plain English. Fora looks like a typo of flora. Back in the day it was a different story. Here’s an excerpt from the translation of L’Histoire des Empereurs des Romains by Jean Baptiste Louis Crévier (1693-1765), printed in London in MDCCLXI.
http://books.google.com/books?id=4bBjAAAAMAAJ&pg=RA1-PA25#v=onepage&q&f=true
The Roman Fora were commonly about three times as long as they were broad. The whole compass of the Forum was surrounded with arched porticos, only some passages being left for places of entrance. Their situation was, generally, so contrived that some of the most stately edifices such as temples, theatres, basilicae, &c. stood round, or near them.
They were of two sorts, Fora Civilia and Fora Venalia. The former were designed for the ornaments of the city, and for the use of public courts of justice; the others, like our markets, were intended for the convenience of the people.
Of the Fora Civilia there were five considerable in Rome, viz.
Augustus’s Forum, built by Augustus Caesar, and reckoned by Pliny among the wonders of the city. The most remarkable curiosity was the statues in the two porticos on each side of the main building. In one, were all the Latin kings, beginning with Aeneas; in the other, all the kings of Rome, beginning with Romulus; most of the eminent persons in the commonwealth, and Augustus himself among the rest; with an inscription upon the pedestal of every statue expressing the chief actions and exploits of the person it represented. This Forum was restored by the emperor Adrian.
Caesar’s, or the Julian Forum, built by Julius Caesar, with the spoils taken in the Gallic war. It’s area alone, Suetonius tells us, "cost a hundred thousand sesterces; and Dio affirms it to have much exceeded the Roman Forum.
Nerva’s Forum, b