A Klingon mummification glyph was a form of carved pictograph writing used by the Klingons.
Background information Edit
The Klingon mummification glyph seen in the fourth movie was identified in the script as coming from the earliest part of the Zanxthkolt Dynasty. The movie was not so specific.
The practice of mummification would seem to indicate that Klingons valued the bodies of their dead at some point, in contradiction to the episode "Heart of Glory"; where the Klingon body was considered an 'empty shell' immediately upon death. It should be noted that this idea was also seemingly contradicted by the practice of ak'voh. However like it ak'voh it could represent an ancient and antiquated position that is no longer commonly observed, it might also be possible that only the remains of certain important individuals were preserved. A further hint can be found in "Emanations", where in an unfortunately unfinished sentence Chakotay seems to hint at archeological digs on the Klingon homeworld complicating the picture of Klingons not having burial rituals. At least the ancient ruler Molor might in fact have been mummified, since some entrepreneurs on Maranga IV claimed to have Molor's mummified head on display for a fee of 50 darseks per person. (TNG: "Firstborn")