The Klingon language has become the most popular fictional language in the world, but it began as a few simple words developed by James Doohan, the actor who played Scotty on the Original Series. It was later developed by linguist Marc Okrand into a more complex language.

Qo'noS, translated as "Kronos" in English, is the capital of the Klingon Empire. It includes a lone, huge land mass with a vast ocean, a severely tilted axis that causes wild seasonal changes, a turbulent atmosphere and extremes of both warm and frigid weather.

The dishonor of the father dishonors his sons and their sons for three generations.

In "Errand of Mercy", Captain Kirk and Mr. Spock attempt to sway the incomprehensibly placid population of a planet near the Klingon border to resist an invading military occupation.

According to Klingon mythology, the first bat'leth, or "sword of honor", was forged by Kahless the Unforgettable in the 9th century.

In "The Trouble with Tribbles", a previously-unknown species of small, unbearably cute, voraciously hungry, and rapidly-multiplying furry creatures expose a surgically-altered Klingon spy and save the day.

Following the fall of the Second Dynasty, the Klingon Empire was ruled by a council elected by the people. This was the first and only experiment in Klingon democracy. The experiment ended after just ten years and was afterwards referred to as "The Dark Time".

Kortar and his mate destroyed the gods who created them, and as punishment, Kortar was condemned to ferry the souls of the dishonored to Gre'thor on the Barge of the Dead.

The destruction of Praxis was a plot point in Star Trek VI: The Undiscovered Country, the after-effects driving the plot of the film and later events in the television series Star Trek: The Next Generation.

Worf spent most of his first year on the Enterprise-D as a relief officer for the conn and other bridge stations. Following the death of Natasha Yar at the hands of the Armus entity, he became acting security chief.