stadias

/ˈsteɪdiəs/
noun
  1. Plural of stadia; a surveying instrument for measuring distances, or the marks on a surveying instrument used for distance measurement.
    • Modern laser rangefinders have largely replaced the old stadias in field work.
    • He carefully read the stadias through the telescope to calculate the width of the river.
    • The surveyor adjusted the stadias to get an accurate reading of the distance.