Those of you old enough to remember when the first Street Fighter came out in the '80s might also recall that the PC Engine / TG-16 home port of the game went by the name of Fighting Street (this same version made its way to the Wii Virtual Console later on, too).
There has been much discussion over the decades about why this happened, and the most commonly accepted explanation was that a pre-existing trademark was in place for a pair of trainers, and that forced a name change. However, Yoshiki Okamoto, who would produce Street Fighter II, the infinitely more successful sequel, has apparently revealed the true reason behind the alteration.
Speaking on his YouTube channel (thanks, James Wragg), Okamoto gives the real reason: Namco owns the trademark for the name 'Street Fight', which means any application to use a similar name would have incurred a licence fee.
Given that Street Fighter, while popular, was not the multimedia monster it was by the time its sequel arrived, this fee would have hit the profits of the PC Engine port dramatically, so the choice made to avoid paying by tinkering with the title a little to avoid confusion with Namco's trademark.
Amazingly, Okamoto adds that Capcom did eventually stump up the fee to Namco for Street Fighter II and III (he was the producer on both), and is possibly still paying it (to Bandai Namco) as of 2021.
Okamoto left Capcom to form Flagship in 1997, a firm that would continue to work closely with Capcom, before founding Game Republic in 2003. More recently, he worked on Monster Strike, which is currently the second-highest-grossing mobile app of all time.
You can play the original version of Street Fighter by investing in the excellent 30th Anniversary Collection on Switch, if you fancy it.