Defiant class

The Defiant-class was a type of Federation starship in use by Starfleet in the 24th century. Although officially designated as an escort, the Defiant ships were the first type of starship Starfleet ever created as a dedicated-purpose warship, and they are sometimes referred to as destroyers. '''

The USS Defiant (NX-74205) was the first of what was to be a new Federation battle fleet. Starfleet abandoned the project when the Borg threat became less urgent; also, design flaws turned up, nearly destroying the Defiant during its initial shakedown cruise.

The Defiant prototype was pulled out of storage in 2371 when the Dominion threat emerged. After several upgrades by Deep Space 9 Operations Chief Miles O'Brien, the ship was deemed worthy of use and more ships of the class were constructed.