A raptor was a predatory bird, also referred to as a "bird of prey." Raptor can also refer to the Velociraptor.
Imagery of the raptor was present on ancient Vulcan, where a huge faction of the population "marched beneath the raptor's wings." They were against the teachings of Surak, and killed him using atomic weaponry. (ENT: "The Forge")
The Romulans and Klingons both used spacecraft classified as "Birds-of-Prey." (TOS: "Balance of Terror"; Star Trek III: The Search for Spock)
The Klingons also had Raptor-class starships in the 22nd century. (ENT: "Sleeping Dogs")