In starship classification, a warbird is a type of large warship, such as a battle cruiser. Generally they resemble large predatory birds. (TNG: "The Defector"; TOS: "Balance of Terror")
Three cultures are known to operate warbirds:
- Klingon Empire -Klingon warbird (ENT: "Broken Bow")
- Romulan Star Empire -Warbird of the 22nd century, D'deridex-class warbird (TNG: "The Defector"), Valdore-type (Star Trek Nemesis)
- Remans - Scimitar, a prototype referred to as a "Reman warbird" (Star Trek Nemesis)
The term Warbird, as used within the Romulan Empire, dates back as far as 2154, as the Romulan drone ship was a modified Warbird; this, however, was most likely a Warbird of a much earlier design than that of the D'deridex-class. The term was known to Starfleet as early as the 2344 encounter with the USS Enterprise-C. It is, however, unclear if this specifically refers to the D'deridex-class design or that of yet another unknown Warbird class.
The word in the Romulan language apparently is "D'deridex", as what Data refers to in the episode ""Tin Man" as a "D'deridex class cruiser" is also referred to as a "Warbird class starship" by Picard in "The Defector".
Prior to Star Trek: Enterprise and Star Trek Nemesis, "warbird" or "Romulan warbird" were used exclusively to refer to D'deridex-class starships. Brannon Braga has mentioned that the use of the term "warbird" to describe Klingon ships in "Broken Bow" was a mistake, implying that the production team only wished Romulan ships to be identified as warbirds.