Source : Webster's Revised Unabridged Dictionary (1913)

Flagstaff \Flag"staff`\, n.; pl. {-staves}or {-staffs}.
   A staff on which a flag is hoisted.

Source : WordNet®

Flagstaff
     n 1: a town in north central Arizona; site of an important
          observatory
     2: a tall staff or pole on which a flag is raised [syn: {flagpole}]