untitled
adj.not having a name or title. You use this to describe a book, song, or painting that the creator did not name.
adj.lacking a formal title or name. Often used to describe creative works or documents that remain unnamed by their author.
“The artist left the painting untitled.”
“The band's third album was released as an untitled collection of songs, leaving fans to invent their own names for the tracks.”
“Scholars often refer to the untitled manuscript by its opening line, as the author died before providing a formal heading for the work.”
Typically used as a predicative adjective after a linking verb or as a postpositive modifier following the noun it describes.
From un- + titled.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.