The runic lettering designed by Daeron, the minstrel of Doriath during the Ages of the Stars. This form of letters was designed for inscriptions on hard materials such as stone and wood. As such, it is formed of straight lines. Though it was not especially popular among the Sindar until somewhat later, the cirth were soon in common use among the Dwarves.
These were the runes in which the inscription on the tomb of Balin was written, though they were there called Daeron's Runes by Gandalf.
This form of lettering was also called the Cirtar.