Tengwar is the most prominent of Tolkien's invented writing systems. (The name can be translated as "letters", which is why I will mostly use it as a plural word.) The best known example is undoubtedly the Ring-inscription from The Lord of the Rings. The Tengwar also appear in the illustration for the Moria gate, and Appendix E of the novel contains a detailed description of the system.

The angular letters on Balin's tomb, however, are Cirth ("runes"), and will not be discussed here.

In their fictional setting, the Tengwar came to be known in a wide geographic area, and were used for writing many Elvish and non-Elvish languages. As is to be expected, each language had a somewhat different orthography, or even several of them. These orthographies, the different ways of applying the letters and signs for representing sounds, are known as modes.