stadia

ot noun

1. A level staff or graduated rod used by surveyors to measure differences in level, or to measure horizontal distances by sighting the stadia hairs (graduations) through a telescope.
2. (historically) A graduated brass triangle used to measure the distance of a target by comparison of the graduations with the heights of soldiers or horses.
3. A Greek unit of measurement, equivalent to six plethra or six hundred podes, which, though varying in precise length, is generally accepted to be equivalent to approximately 185·4 metres.
4. A venue where sporting events are held.