Tir

tir- is a Quenya prefix meaning "watch, guard, heed". Compare with the Sindarin noun tirith.

Examples:

• palantíri = "Watch Far and Wide" (colloquially translated as "Seeing-stones")
• Tirion = "[City of] the Watchers"

References

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