The script J.R.R. Tolkien created for writing many of his fictional languages is Tengwar.
Tengwar is a writing system used across Tolkien’s legendarium. In the stories, the Elf Fëanor devised it, and different peoples adapted it for languages including Quenya, Sindarin, and the Common Speech. Tolkien designed the system so that its letters represented sounds, with modes adjusted for different languages.
The script is often seen in inscriptions, maps, title pages, and fan reproductions of Tolkien’s work. Its flowing forms can look like an alphabet, but Tengwar is more accurately described as an abugida or featural writing system, depending on the mode and analysis.
Cirth is a different Tolkien script, characterized by angular runes. Sarati is another earlier system in the fictional history. These names are common sources of confusion because Tolkien developed several writing systems rather than one universal alphabet.