Tengwar is Tolkien’s name for the Elvish writing system used for languages such as Quenya and Sindarin.
Tengwar means “letters” in Quenya. Tolkien designed the script as part of his wider work on invented languages, and its signs represent consonants and vowels through a system of tehtar and consonantal characters. The script is frequently called the Fëanorian script because Tolkien’s mythology attributes its creation to the Elf Fëanor.
Tengwar is not itself a spoken language. It can be used to write several languages, including Quenya, Sindarin, and sometimes languages of Men. The same script can therefore appear with different spelling conventions depending on the language being written.
A common mix-up is Cirth, another Tolkien writing system. Cirth uses angular runic characters and is especially associated with Dwarves, although other peoples also use it. Sarati is an earlier script in Tolkien’s invented writing history, while Tengwar became the best-known Elvish script in The Lord of the Rings appendices and related material.