D defs.my
Entry 2 senses Webster, 1913

Cross-staff

/(-st?f`)/ · Cross·-staff · IPA
01 n. An instrument formerly used at sea for taking the altitudes of celestial bodies.
  1. 1.
    An instrument formerly used at sea for taking the altitudes of celestial bodies.
  2. 2.
    A surveyor's instrument for measuring offsets.