-ndur

-dur or -ndur is a Quenya suffix added to names to indicate faithful service or servitude.

Examples:

• Eärendur = "Servant of the Sea"
• Valandur = "Servent of the Valar"

References

• The Languages of Tolkien's Middle-earth by Ruth S. Noel
• Quenya Corpus Wordlist edited by Helge Kåre Fauskanger