Klingon Imperial Fleet

From Memory Alpha, the free Star Trek reference

The Klingon Imperial Fleet is the name for the starship fleet and military personnel serving under the Klingon Empire during the 22nd and 23rd century.

Antaak served as a physician in the Imperial Fleet during the 2150s. (ENT: "Divergence") Kuri served as a commander in the Imperial Fleet during the 2260s, where he commanded a D7 class Klingon battle cruiser. (TAS: "The Time Trap")

The records of the Imperial Fleet mentioned Jonathan Archer's instrumental assistance in the rescue of the Klingon Raptor, Somraw, from the dense atmosphere of a gas giant. (ENT: "Judgment")

Few engineers in the Imperial Fleet knew how to operate cloaking devices when they were introduced, necessitating Kor's need to study the device himself when the Klothos left Qo'noS to attack Caleb IV. (DS9: "Once More Unto the Breach")

It is unknown if the usage of the term "Imperial Fleet" went into disuse by the 24th century or became merged with or renamed as the Defense Forces. One might assume that the so-called "Imperial Klingon Cruiser" Amar and the prefix "IKS" are somehow related to, and a potential variation of the name, Imperial Klingon Fleet.