Star Trek: Deep Space Nine's Defiant originally had another name

Introduced in Star Trek: Deep Space Nine's first episode of season three, the USS Defiant became the weapon for Captain Sisko to use to help defeat the Foundlings in the Dominion War. Prior to this, Sisko and his crew, with the exception of the occasional use of runabouts, were confined to the space station. The introduction of the war made it necessary for Sisko to have acces to a ship.

"The Search Part 1" was written by Ronald D. Moore. It was his first time writing for Deep Space Nine, and, according to Screenrant, he was excited about introducing the series' first warship. He named the ship the USS Valiant, based on two ships that were a part of two Star Trek: The Original Series' episodes—"Where No Man Has Gone before" and "A Taste of Armageddon." Unfortunately, though, this name was declined by executive producers Rick Berm and Michael Pillar because, with Star Trek: Voyager in production, they didn't want another ship starting with the letter "V."

Moore went back to the drawing board, so to speak, meaning he recruited another name from an episode from The Original Series. Deep Space Nine's warship was named the USS Defiant after a ship in "The Tholian Web." The writers gave the reason for the warship's name by adding in a layer that it was meant to be able to withstand a battle against the Borg because of the Battle of Worf 359.

Deep Space Nine finally introduced a USS Valiant three years later in the season five Nog-centric episode "Valiant," which was helmed by the Red Squad, a team of Starfleet Academy cadets. But this starship was doomed to fail much like its predecessors, and it was lost when the leader of the Red Squad undertook a mission to destroy a Jem'Hadar warship.

Only die-hard Star Trek fans would have remembered the name of the two ships used in The Original Series, and most likely, no fan would have cared if the USS Defiant had been christened the USS Valiant instead. But the Defiant did become a large part of the battle in the Dominion War before it was destroyed in the season seven episode"The Changing Face of Evil."