Why is the forum in Rome named the forum?

The Roman Forum, also known by its Latin name Forum Romanum (Italian: Foro Romano), is a rectangular forum (plaza) surrounded by the ruins of several important ancient government buildings at the center of the city of Rome. Citizens of the ancient city referred to this space, originally a marketplace, as the Forum Magnum, or simply the Forum.

For centuries the Forum was the center of day-to-day life in Rome: the site of triumphal processions and elections; the venue for public speeches, criminal trials, and gladiatorial matches; and the nucleus of commercial affairs. Here statues and monuments commemorated the city's great men. The teeming heart of ancient Rome, it has been called the most celebrated meeting place in the world, and in all history. Located in the small valley between the Palatine and Capitoline Hills, the Forum today is a sprawling ruin of architectural fragments and intermittent archaeological excavations attracting 4.5 million or more sightseers yearly.

The Forum in Rome is the location of the ruins of the ancient city of Rome.  The forum is derived from Latin, meaning rectangular plaza.  The plaza was the center of activity in Rome.  Staging speeches trials and public gatherings.