Fiftieth (adjective)

1. The ordinal number corresponding to the number 50.
2. The 50th item in a series.

Origin:

Early 17th century: from fifty + -th.

Examples:

1. He celebrated his fiftieth birthday last week.
2. This is the fiftieth anniversary of the company's founding.
3. The fiftieth page of the book was missing.
4. He was the fiftieth person to finish the marathon.
5. The fiftieth state to join the Union was Hawaii.