xix
n. C2 Proficiency xix
n. the nineteenth number. You use it when you are writing numbers in Roman numerals, like for a chapter in a book.
n. the Roman numeral representing the number nineteen.
The chapter is labeled as Chapter XIX.
The library catalog lists the book as being from the nineteenth century, though the Roman numeral on the spine reads XIX.
In the final act of the play, the protagonist is introduced as the nineteenth son of a noble family, a detail noted in the margin as XIX.